Exhibit 4.18**AMENDMENT NO. 5, WAIVER AND CONSENT**          Amendment No. 5, Waiver and Consent, dated as of April 3, 2007 (this “Amendment No.5”), relating to the Investment and Note Purchase Agreement (as amended by Amendments No. 1through No. 4 thereto, the “Existing Agreement”), dated as of June 23, 2005, by and amongViatel Holding (Bermuda) Limited (the “Company”) and the purchasers named therein and theCompany’s Senior Secured Increasing Rate Notes Due 2007 (the “New Notes”). Capitalizedterms used in this Amendment No. 5 and not defined shall have the meanings assigned to them in theExisting Agreement.          WHEREAS, the parties hereto have agreed that the parties set forth on Schedule I attachedhereto (“New Purchasers”) will purchase additional New Notes in an aggregate principalamount equal to $13,011,120.00 (“April 2007 Notes”);          WHEREAS, the parties have agreed, subject to and upon the terms and conditions set forthherein, to amend the Existing Agreement as set forth herein in order to provide for the April 2007Notes;          WHEREAS, the Board of Directors of the Company has determined that entering into thisAmendment No. 5 and related documentation is in the best interests of the Company and have approvedand authorized the execution of the documents necessary to give effect to this Amendment No. 5 andrelated documentation; and          WHEREAS, each of the holders of the New Notes (the “New Holders”) has determined thatthis Amendment No. 5 is in its best interests and has approved this Amendment No. 5;          NOW, THEREFORE, the parties hereto, intending to be legally bound, hereby agree as follows.     1. Consent to Special Share Holder Action. Each New Holder hereby consents to theholder of the Special Share entering into a consent pursuant to Section 76A of the Company’sbye-laws that will allow the Company to issue the April 2007 Notes pursuant to this Amendment No. 5and to execute any other documents or transactions related thereto.     2. Amendment to Existing Agreement. Each of the Company and each New Holder herebyagrees that the Existing Agreement is hereby amended by:          (i) Replacing the second paragraph of the recitals with the following paragraph:          “WHEREAS, the Company proposes to issue and sell US$16,000,000 aggregate principal amount ofits Senior Secured Increasing Rate Notes due 2007 (the “2005 Notes”), US$8,802,600aggregate principal amount of its Tranche A Senior Secured Increasing Rate Notes due 2007 (the“2006 Notes”), US$13,011,120.00 aggregate principal amount of its Tranche B Senior SecuredIncreasing Rate Notes due 2007 (the “December 2006 Notes”) and US$13,011,120.00 aggregateprincipal amount of its Tranche C Senior Secured Increasing Rate Notes due 2007 (the “April2007 Notes”) to the several Purchasers;”
 

 
          (ii) Inserting the following new definition in alphabetical order in Section 1.01 of theExisting Agreement:          ““April 2007 Notes” has the meaning set forth in the recitals.”          (iii) Replacing the definition of Notes in Section 1.01 with the following definition:          ““Notes” means the 2005 Notes, the 2006 Notes, the December 2006 Notes and the April2007 Notes.”          (iv) Replacing the existing Schedule I with the Schedule I attached hereto.     3. Waiver to 2005 Notes and 2006 Notes.          (i) For the avoidance of doubt, the holders of the 2005 Notes, the holders of the 2006 Notesand the holders of the December 2006 Notes hereby agree to waive the requirement pursuant toSection 5.2(d) of such notes that the Company use the proceeds of the issuance of the New Notes toredeem such 2005 Notes, 2006 Notes and December 2006 Notes.     4. Delivery of and Payment for the Notes.          (i) Subject to the terms and conditions set forth herein and in the Existing Agreement,delivery of and payment for the April 2007 Notes shall be made at the offices of Wachtell, Lipton,Rosen & Katz, or at such other place as shall be agreed upon by the New Purchasers and the Company,at 10:00 am (New York time) on the first Business Day following the satisfaction or waiver of allof the conditions set forth in paragraph 6 hereof (other than those conditions that by their natureare to be satisfied or waived on the Amendment No. 5 Closing Date, but subject to the satisfactionor waiver of those conditions), or at such other time and date as shall be agreed upon by the NewPurchasers and the Company (such date and time of payment and delivery being referred to herein asthe “Amendment No. 5 Closing Date”).          (ii) On the Amendment No. 5 Closing Date, payment of the purchase price for the April 2007Notes shall be made to the Company by wire or book-entry transfer in immediately available funds tosuch account or accounts as the Company shall specify prior to the Amendment No. 5 Closing Date orby such other means as the parties hereto shall agree prior to the Amendment No. 5 Closing Dateagainst delivery to the New Purchasers of the certificates evidencing the April 2007 Notes. Timeshall be of the essence, and delivery at the time and place specified pursuant to this AmendmentNo. 5 is a further condition of the obligations of the New Purchasers hereunder. Upon delivery,the April 2007 Notes shall be in definitive certificated form, registered in such names and in suchdenominations as the New Purchasers shall have requested in writing prior to the Amendment No. 5Closing Date.          (iii) When delivered by the Company on the Amendment No. 5 Closing Date, the April 2007 Notesshall be fully authorized, duly and validly issued, and free and clear of Liens (other than Liensspecifically contemplated by the Transaction Documents).
 

 
     5. Further Assurances. In consideration for the purchase of the April 2007 Notes andother consideration provided for in this Amendment No. 5, as security for the due and punctualpayment of the April 2007 Notes, the Company agrees that at any time and from time to time, at theCompany’s expense, the Company will promptly execute and deliver all further instruments anddocuments, and take all further action that the Lenders may reasonably request, in order to perfectand protect the Security Interest (as defined in the New Notes) granted in respect of the New Notesor to enable the New Holders to exercise or enforce their rights, powers and remedies with respectto the Security Interest and any other collateral that may secure the New Notes in the future.     6. Representations and Warranties.          (i) The Company represents and warrants to, and agrees with, the New Holders that:               (a) The Company has the corporate power and authority to execute, deliver and perform, asapplicable, its obligations under this Amendment No. 5 and any other documents contemplated herebyto which it is or will be a party;               (b) The execution, delivery and performance of this Amendment No. 5 (a) have been dulyauthorized by all necessary corporate action on the part of the Company, (b) will not constitute aviolation of any provision of any Applicable Law or any order of any Governmental Authorityapplicable to the Company or any of its properties or assets, (c) will not violate any provision ofthe charter, bye-laws, or any other organizational document of, or other similar instrument towhich the Company is a party or by which the Company or any of its properties or assets are boundor to which the Company is subject, (d) will not be in conflict with, result in a breach of, orconstitute (with due notice or lapse of time or both) a default under, or create any right toterminate, any indenture, agreement, bond, note, mortgage, deed of trust, or other instrument towhich the Company is a party or by which the Company or any of its properties or assets are boundor to which the Company is subject and (e) will not result in the creation or imposition of (or theobligation to create or impose) any lien, charge or encumbrance of any nature whatsoever upon anyof the properties or assets of the Company other than pursuant to the Security Documents or theother Transaction Documents (as amended);               (c) Upon its execution and delivery by the Company, this Amendment No. 5 and each TransactionDocument amended pursuant hereto shall constitute or continue to constitute the legal, valid andbinding obligation of the Company, enforceable against the Company in accordance with its terms,except as such enforceability may be limited by applicable bankruptcy, insolvency and similar lawsaffecting creditors’ rights generally and to general principles of equity, irrespective of whethersuch enforceability is considered in a proceeding at law or equity;               (d) The Company is not in violation of any Applicable Law or any restrictions of record oragreements affecting the Security Interest, except for violations which in the aggregate could notreasonably be expected to have a Material Adverse Effect;
 

 
               (e) As of the Amendment No. 5 Closing Date, there are no outstanding Defaults or Events ofDefault (as defined in the New Notes) under the existing New Notes;               (f) The April 2007 Notes constitute Notes under the Existing Agreement and the otherTransaction Documents, including, without limitation, the Security Documents; and               (g) All representations and warranties set forth in the Existing Agreement and the otherTransaction Documents are true and correct in all material respects on and as of the Amendment No.5 Closing Date with the same effect as if made on and as of such date, except to the extent suchrepresentations and warranties expressly relate to an earlier date or to the extent qualified bythe disclosure schedules hereto.          (ii) Each Purchaser severally as to itself, and not jointly, hereby represents and warrants tothe Company on the date hereof that all representations and warranties set forth in Section 4.02 ofthe Existing Agreement are true and correct in all material respects on and as of the date of theAmendment No. 5 Closing Date with the same effect as if made on and as of such date.     7. Conditions to Effectiveness. This Amendment No. 5 shall become effective on thedate upon which the New Holders notify the Company that they are satisfied that each of thefollowing conditions have been met:          (i) The New Holders shall have received an executed counterpart of this Amendment No. 5bearing the signature of the Company;          (ii) The Company shall have delivered to the New Holders such other documents, agreements,instruments and information as the New Holders may reasonably request;          (iii) The Company shall have included, in the principal amount of the December 2006 Notes, anamendment fee equal to 2% of the purchase price of the April 2007 Notes, set forth as the “PurchasePrice of April 2007 Notes” in Schedule I attached hereto.          (iv) The New Holders shall have received reimbursement or other payment of all reasonablecosts, fees and expenses of the Lenders (including, without limitation, the fees and disbursementsof Wachtell, Lipton, Rosen & Katz), incurred in connection with this Amendment No. 5, and all otherdocuments to be delivered in connection herewith;          (v) The representations and warranties set forth herein and in Article III of the ExistingAgreement and in any other Transaction Documents then in existence shall be true and correct in allmaterial respects, and no Default or Event of Default under the existing New Notes shall haveoccurred and be continuing; and          (v) The Company, the Law Debenture Trust Corporation P.L.C. and the holders of the 2005 Notesshall have executed and delivered to the New Holders an executed counterpart of Amendment No. 2 tothe Subordination Agreement dated as of March 14, 2006,between the holders of the 2005 Notes, which amendment shall be in form and substance satisfactoryto the New Holders.
 

 
     8. Governing Law; Jurisdiction; Waiver of Trial by Jury. This Amendment No. 5 shallbe construed in accordance with the internal laws of the State of New York without regard to theconflicts of laws provisions thereof. Each party hereto hereby irrevocably submits to thejurisdiction of any court of the State of New York located in the County of New York or the UnitedStates District Court for the Southern District of the State of New York, any appellate courts fromany thereof (any such court, a “New York Court”) or any court of the United Kingdom locatedin London, or any appellate courts from any thereof (any such court, a “U.K. Court”), forthe purpose of any suit, action or other proceeding arising out of or relating to this AmendmentNo. 5 or under any applicable securities laws and arising out of the foregoing, which is brought byor against such party, and each such party hereby irrevocably agrees that all claims in respect ofany such suit, action or proceeding will be heard and determined in any New York Court or U.K.Court. Each such party hereby agrees not to commence any action, suit or proceeding relating tothis Amendment No. 5 other than in a New York Court except to the extent mandated by applicablelaw. Each such party hereby waives any objection that it may now or hereafter have to the venue ofany such suit, action or proceeding in any such court or that such suit, action or proceeding wasbrought in an inconvenient court and agree not to plead or claim the same. EACH PARTY TO THISAMENDMENT NO. 5 HEREBY EXPRESSLY WAIVES ANY RIGHT TO TRIAL BY JURY OF ANY CLAIM, DEMAND, ACTION ORCAUSE OF ACTION ARISING UNDER THIS AMENDMENT NO. 5 OR IN ANY WAY CONNECTED WITH OR RELATED ORINCIDENTAL TO THE DEALINGS OF THE PARTIES HERETO OR ANY OF THEM WITH RESPECT THIS AMENDMENT NO. 5,OR THE TRANSACTIONS RELATED HERETO, IN EACH CASE WHETHER NOW EXISTING OR HEREAFTER ARISING, ANDWHETHER FOUNDED IN CONTRACT OR TORT OR OTHERWISE; AND EACH PARTY HEREBY AGREES AND CONSENTS THATANY SUCH CLAIM, DEMAND, ACTION OR CAUSE OF ACTION SHALL BE DECIDED BY COURT TRIAL WITHOUT A JURY,AND THAT ANY PARTY TO THIS WAIVER AND CONSENT MAY FILE AN ORIGINAL COUNTERPART OR A COPY OF THISSECTION WITH ANY COURT AS WRITTEN EVIDENCE OF THE CONSENT OF THE SIGNATORIES HERETO TO THE WAIVEROF THEIR RIGHT TO TRIAL BY JURY.     9. Separability. If any one or more of the provisions contained in this Amendment No.5 shall, for any reason, be held to be invalid, illegal or unenforceable in any respect, suchinvalidity, illegality or unenforceability shall not affect any other provisions of this AmendmentNo. 5 and such provision shall be interpreted to the fullest extent permitted by the law; *provided*that the Company and each New Holder shall use their reasonable best efforts to find and employ analternative means to achieve the same or substantially the same result as that contemplated by suchprovision.     10. Successors and Assigns. All agreements of the Company and the New Holdershereunder shall bind their respective successors and assigns.[REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]
 

 
     IN WITNESS HEREOF, THE PARTIES HERETO HAVE CAUSED THIS AMENDMENT NO. 5 TO BE DULY EXECUTED AS OFTHE DATE FIRST WRITTEN ABOVE:VIATEL HOLDING (BERMUDA) LIMITED     By: /s/ Lucy Woods    Name: Lucy Woods    Title: Chief Executive Officer  [SIGNATURE PAGE TO AMENDMENT TO INVESTMENT