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

    


    WHEREAS Guildhall 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 WHEREAS Guildhall IS
restructuring itself to engage In oil and gas exploration, development and
production. AND WHEREAS Guildhall 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 WHEREAS British 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 WHEREAS Guildhall wishes
to acquire BANG for the exploration potential of its Interests.

     

    AND WHEREAS BANG 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 WHEREAS BANG 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.

     

    AND WHEREAS BANG 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 WHEREAS BANG 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 WHEREAS David 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 WHEREAS BANG'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 WHEREAS concurrently 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").

     

    
      
         

      

      
        Exhibit
4.3

        
          

        

      

      
         

      

    

     

    AND WHEREAS it 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 THEREFORE for 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 ofNEX.

            


    

    


    
      	
              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 51-10 I) to prepare
      a report on all or a portion of the Interests in compliance with NI51-101.
      II. 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.

            


    

     

    
      
         

      

      
        Exhibit
4.3

        
          

        

      

      
         

      

    

     

    
      	
              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 I,
      2009 and the remaining 25% shall vest on January 1,
      2010.

            


    

    


    
      	
              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.

            


    

    


    
      	
              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:

                      	 
      	 
      
	 
      	 
      	
                        Michael
      M.D. Laidlaw,
President

                      


              

            

          

        

      

    

    


    BRITISH
AMERICAN NATURAL GAS

    CORPORATION

    


    
      
        
          
            	
                    Per:

                  	 
      	 
      
	 
      	 
      	
                    David
      A. Melman, President and
CEO

                  


          

        

      

    


    
      
         


      

      
        Exhibit
4.3