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Exhibit 4.3

GUILDHALL
MINERALS LTD.320 -
1100 Melville Street Vancouver, B.C.
V6E 4A5 Tel: (604) 688-3931 Fax: (604) 688-2921

May 1, 2008

British
American Natural Gas Corporation 520 Post Oak Blvd., Suite 275 Houston, Texas, USA
77027

Attention:
          Mr. David Melman,
Pres. & CEO

LETTER OF INTENT

WHEREASGuildhall Minerals Ltd.
(Guildhall) is a British Columbia company, the shares of which are listed for
trading on the NEX board (NEX) of the TSX Venture Exchange (the TSXV) in Canada. Guildhall is a reporting
issuer in the provinces in British Columbia and Alberta. It is also registered with the U.S.
SEC pursuant to the filing of a 20-F Registration Statement. The shares are
also quoted for trading on the NASD OTC Bulletin Board. It has 16,643,012 voting
common shares issued. It has no other shares issued. Its authorized capital
consists of an unlimited number of voting common shares without par value. It has approximately
$625,000 cash on hand and no debts except current trade debts.

AND WHEREASGuildhall is restructuring
itself to engage in oil and gas exploration, development and production.

AND WHEREASGuildhall has agreed to acquire
First West Petroleum Inc. (First West) for the
issuance of 26,000,000 shares of Guildhall Common Stock in order to acquire
producing oil and gas assets in Canada.

AND WHEREASBritish American Natural Gas
Corporation (BANG) is a private Nevada company which is the owner of
interests in concessions (Interests) covering approximately 11,400,000 acres
onshore and offshore Mozambique  which are held in four wholly owned
subsidiary corporations, three incorporated in Mauritius and one in The
Bahamas.

AND WHEREASGuildhall wishes to acquire
BANG for the exploration potential of its Interests.

AND WHEREASBANG has maturing contractual
obligations with respect to funding participation in one exploration well and
potentially two appraisal wells to be drilled on the Interests which will require a
$2,000,000 loan to be available by June 17, 2008 (the Interim Funding).

AND WHEREASBANG has 9,361,597 shares of
Common Stock issued and outstanding held by 22 registered or beneficial
shareholders which are to be acquired by Guildhall for the issuance of 46,807,985 shares of Guildhall Common Stock.

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AND WHEREASBANG has 2,080,345 Preferred
Stock issued and outstanding (BANG Preferred Shares), the holders of which have the right to convert them
into shares of Common Stock or which are automatically converted to or
exchanged for shares of Common Stock on the occurrence of certain events  and
it is expected that the within agreement will trigger the exchange of such
shares for 10,401,725 shares of Guildhall
Common Stock.

AND WHEREASBANG also has warrants outstanding
(BANG Warrants) to purchase shares of BANG Common Stock which will be exchanged for
new warrants to acquire 7,634,930 shares of Guildhall Common Stock at $0.75 per share.

AND WHEREASDavid Melman (Melman), the
President and Chief Executive of BANG, holds options to purchase 900,000 shares of BANG
Common Stock which options are to be exchanges for options to purchase 4,500,000 shares of
Guildhall Common Stock at a price of $0.75 per share.

AND WHEREASBANGs legal and tax advisors
have advised that the preferred way of effecting the acquisition of BANG by Guildhall is for Guildhall to
purchase all issued and outstanding shares
of BANG in consideration for the issuance and allotment of 57,209,710 of
Guildhall Common Stock (the Acquisition).

AND WHEREASconcurrently with the closing
of Guildhalls acquisition of First West and BANG, the parties wish
for Guildhall to graduate to the Toronto Stock Exchange (the Exchange).

AND WHEREASit is recognized that, to have
the within transaction accepted by the Exchange, the TSXV and NEX, as the case
may be, Guildhall will have to present to the Exchange, the TSXV and NEX, as the case may be, at least:

| |                                                                                                                                                                                                                 
| | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
| | (a)     a report on all or a
  portion of the Interests prepared in compliance with the requirements of Canadian National Instrument 51-101  Standards of Disclosure for Oil and Gas Activities(NI
  51-101);
| |                                                                                                                                                                                                                 
| | (b)     financial
  statements of BANG audited to December 31, 2007 with comparative figures for the two previous years;                                                                                        
| |                                                                                                                                                                                                                 
| | (c)     a sponsorship
  agreement;                                                                                                                                                                              
| |                                                                                                                                                                                                                 
| | (d)     Form 4 Personal Information Forms completed by
  the persons who will be the directors, officers and insiders of Guildhall
  upon the completion of the within transaction.                             

NOW THEREFOREfor good and valuable
consideration, the receipt and sufficiency of which we hereby acknowledge the
Parties hereto agree that:

|   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
|-- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|1. | Guildhall
  is to enter into a support agreement with First West and a lock up agreement
  with each of Chris Wright and Sam Davaraj (together, the FW Controlling
  Shareholders), whereby Guildhall agrees to purchase all of the issued and
  outstanding share capital of First West and the FW Controlling Shareholders
  agree to tender their shares to a formal take-over bid of First West by Guildhall.                                                                                                                                                                                                                                   
|   |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
|2. | Guildhall
  will initiate an application to have the common shares of Guildhall listed on
  the Exchange
  and to have the within transaction approved by the Exchange and will, in that
  respect, comply
  with the requirements of the Exchange. If Guildhall does not meet the listing
  requirements
  of the Exchange, Guildhall will initiate an application to have the common
  shares of Guildhall
  listed on the TSXV and to have the within transaction approved by the TSXV
  and will, in that respect, comply with the requirements of the TSXV.
  Guildhall will also comply with the reactivation and other applicable rules of NEX.

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|    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|--- | -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|3.  | Guildhall
  will hold a Special Meeting of its shareholders and seek approval of the
  within transaction and if applicable, the acquisition of First West,
  including listing of its common shares on the Exchange or the TSXV, as the case may be, the subdivision of
  its issued shares on a 1.5 new for 1.0 old
  basis so that Guildhall has 24,964,518 shares issued and outstanding, the name
  change to British American Natural
  Gas Corporation and appointment of up to six directors, including four nominees chosen by BANG.                                                                                                                                
|    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|4.  | Guildhall will seek and
  secure not less than the requisite special majority approval of Guildhall
  shareholders in support of the within transaction and ancillary actions
  described in paragraph 3 above.                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|5.  | Intentionally
  Deleted.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
|    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|6.  | BANG
  and Melman will seek to have 100% of the BANG Preferred Shares converted to
  BANG Shares
  so that, upon the closing of the within transaction, BANG will have no
  outstanding Preferred
  shares.                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
|    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|7.  | BANG
  and Melman will seek and secure not less than a 67% vote in support of the
  within transaction by
  the shareholders of BANG.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                        
|    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|8.  | All issued and outstanding
  BANG Warrants shall be exchanged for replacement warrants issued by Guildhall to purchase 7,634,930 shares of
  Guildhall Common Stock at $0.75 per Guildhall share.                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
|    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|9.  | Guildhall
  will use its best efforts to engage brokers to secure purchasers for not less
  than 26,666,666
  nor more than 40,000,000 shares of Guildhall Common Stock at a price of not
  less than $0.75 per share to
  provide Guildhall with gross proceeds of at least $20,000,000 nor more than $30,000,000, such share sales to close
  prior to the closing of the Acquisition (the Financing). BANG and Guildhall shall pay to such brokers a cash
  commission of 8% of the gross
  proceeds of the Financing and broker warrants exercisable for 10% of the
  number of shares of Guildhall Common Stock issued pursuant to the
  Financing at $0.75 per share.
|    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|10. | BANG
  shall retain an independent qualified reserves evaluator or auditor (as those
  terms are defined in NI 51-101) to prepare a report on all or a portion of the
  Interests in compliance with NI
  51-101.                                                                                                                                                                                                                                                                                                                                                                                                                                                            
|    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|11. | If the
  closing of the Acquisition does not occur on or prior to June 16, 2008,
  Guildhall will secure and advance to BANG the funds required by BANG to meet
  the Interim Funding requirement. Should
  Guildhall be unable to make such advance, the intended transaction as
  described herein shall be deemed
  terminated with no further liability to anyone of Guildhall, First West or
  BANG.                                                                                                                                                                                                                                                                    
|    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              
|12. | Melman
  will surrender the 900,000 BANG options he holds and Guildhall will,
  concurrently with the closing of the Acquisition, grant him an option to
  acquire 4.5 million shares of Guildhall Common Stock on substantially the same terms as
  the BANG options currently issued to Melman, except that the exercise price shall be
  $0.75 per share provided that the offering described in paragraph 9 is not at a lower price.
  One half of the newly issued options will be fully vested upon the grant date, 25% shall vest
  on January 1, 2009 and the remaining 25% shall vest on January 1, 2010.                                                           

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|13. | All of
  the Parties agree to undertake the satisfaction of their responsibilities and
  obligations expeditiously with a view to having the within Agreement documented,
  accepted by the Exchange or the
  TSXV, as the case may be, and closed at the earliest reasonable date.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
|    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|14. | It is
  acknowledged that the closing of the acquisition by Guildhall of First West,
  the Financing referred to in paragraph 9 and the closing of the within Agreement are
  to occur sequentially following
  the Exchanges, or the TSXVs, as the case may be, acceptance of the
  transactions.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           
|    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|15. | To the extent that neither
  the TSX nor the TSXV policies impose a hold period on the shares of Guildhall Common Stock issued to First West
  shareholders, concurrently with the closing of the acquisition of First West,
  Guildhall shall enter into lock-up agreements with the FW Controlling Shareholders to the effect that neither
  shareholder will offer, sell, contract to sell, pledge or otherwise
  dispose of, (or enter into any transaction which is designed to, or might
  reasonably be expected to, result in the
  disposition by such shareholder or any affiliate of such shareholder), directly or indirectly, any shares of Guildhall
  Common Stock or any securities convertible into, or exercisable or exchangeable for shares of
  Guildhall Common Stock, or publicly announce an intention to effect any such transaction, for
  the period commencing on the closing date and ending on the date that
  is 90 days after the closing date.
|    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|16. | Intentionally
  Deleted.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       
|    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|17. | BANG
  will deliver year end December 31, 2007 financial statements audited pursuant
  to US GAAP standards by
  April 30, 2008.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
|    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|18. | BANG is to expeditiously
  complete due diligence, to be conducted by such counsel, geological consultants, and financial consultants as it,
  in its absolute and sole discretion, chooses to retain to examine the
  business affairs and financial affairs of Guildhall and of First West, and
  the title to and geologic viability of
  the First West Assets;                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            
|    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|19. | Each of the Parties agrees
  to negotiate in good faith to structure the Acquisition in the most tax effective manner to BANG, its shareholders,
  Guildhall and its shareholders. The obligation of BANG to complete the Acquisition is conditional
  upon BANG receiving an opinion of counsel of its choice that the Acquisition will be tax-free in the United States
  and Canada for BANG shareholders.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  
|    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|20. | Each of
  the Parties shall be responsible for its own fees and expenses in connection
  with the Acquisition.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 
|    |                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                
|21. | Time
  is of the essence in this Agreement.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    

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|22. | This
  Agreement shall be governed by the laws of the Province of British Columbia
  and the federal laws of
  Canada applicable therein. Each of the parties agrees to attorn to the
  exclusive jurisdiction of the courts of British Columbia.

AGREED TO effective this 21st
day of May, 2008.

|                                        |                                      | 
|--------------------------------------- | ------------------------------------ | 
|GUILDHALL MINERALS LTD.                 |                                     
|                                        |                                      | 
|Per:                                    | (SIGNATURE)                          | 
|                                        |                                      | 
|                                        | Michael M.D. Laidlaw,
  President    | 
|                                        |                                      | 
|BRITISH AMERICAN NATURAL GASCORPORATION |                                     
|                                        |                                      | 
|Per:                                    | (SIGNATURE)                          | 
|                                        |                                      | 
|                                        | David
  A. Melman, President and CEO | 

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