“… None of the terms of the subcontract shall be varied, waived, discharged or released, except with the prior written agreement of the contractor.”
“The subcontractor shall commence performance of the works on the commencement date. Thereafter, the subcontractor shall proceed with the works with due expedition and without delay and in accordance with the subcontract programme. … Clause 43.1 of the subcontract headed ‘Time for Completion’ provides: “ The works and, if applicable, any section or system, shall be completed on or by the specified dates per unit within this clause, in accordance with the TOP Take Over Performance dates, these being the final entries on page 3 of the programme … Clause 60.1 of the subcontract headed ‘Payment’ provides: “The subcontractor shall be entitled to submit an application for payment to the contractor on a calendar monthly basis by the 20th day of each month ... Applications for payment shall state the value of the work performed to that time, the cumulative amount paid, the current application for payment and balance amount payable ..." Clause 60.2 of the subcontract, under the heading ‘Payment Certificate’ provides: “Within 10 days of receipt of an application for payment the contractor shall carry out an assessment and shall issue to the subcontractor an interim payment certificate stating the amount due … The amount payable in respect of any milestone shall be as listed in the subcontract particulars The subcontractor shall issue an invoice to the contractor for the amount certified by the contractor. Payment of money shall not be evidence of the value of work or an admission of liability or evidence that work has been executed satisfactorily at shall be a payment on account only … The contractor shall be entitled to deduct from, or set off against, any monies due to the subcontractor for any sums which the subcontractor shall be liable to pay the contractor under this subcontract.”
“The contractor may by any interim payment certificate made any correction or modification in any previous interim payment certificate and if any work is not carried out to its reasonable satisfaction then it may omit or reduce the value of such work in any interim payment certificate." Clause 60.9 of the subcontract, under the heading ‘Time for payment’ provides: “ … the amount due … shall be paid … (a) under any interim payment certificate issued by the contractor within 40 days after receipt of the subcontractor's application for payment; …”
“8. By the summer of 2011 it was clear to the defendant that the claimant's works were not being properly planned and supervised, with the result that progress of such works was falling far behind programme. It was also clear to the defendant that this was going to have a critical impact upon completion of the defendant's works for the purposes of its agreement with Alstom, under which the defendant faced the prospect of incurring a substantial liability for liquidated and ascertained damages for delay. 9. The defendant queried the claimant's entitlement to payment of the interim amounts certified as payable to the claimant under clause 60.2 of the contract conditions. This led to a dispute regarding the claimant's entitlement to be paid such monies. The claimant's response was to suspend its works. 10. It was the arguments concerning the claimant's entitlement to payment of interim amounts certified under the two contracts that was one of the main drivers leading to the undated and unsigned agreement between the parties, which has become known as "the December agreement" …”
“11. After the supplemental agreement had been executed,McConnell duly proceeded with the remainder of the works. Following completion of the works, it was necessary to establish what further payments were due to McConnell in addition to the sum of£30.5 million specified in the supplemental agreement. This involved (a) examining the work which was done and the events which occurred after12 December 2002 , (b) identifying which matters were included in the revised contract price of£30.5 million , and (c) evaluating what payments were due to McConnell in respect of matters not included within the revised contract price. 12. NGG paid the sums which they conceded were due. By letter dated … McConnell claimed that it was entitled to a further payment of£1.4 million . This claim was based upon a re-measure of provisional sum items and provisional quantities as well as compensation events said to have occurred after12 December 2002 . 13. NGG rejected McConnell’s claim. By a letter dated ...NGG asserted that most of the matters for which McConnell was claiming additional payment had been settled by the supplemental agreement. 14. By a notice of adjudication … McConnell referred its claim against NGG to adjudication. NGG did not accept that an adjudicator would have jurisdiction. In those circumstances, unsurprisingly the parties did not agree upon the identity of the adjudicator. Accordingly, McConnell applied to the President of the ICE to appoint an adjudicator … the President appointed Mr Elven to act as adjudicator. 15. NGG maintained that Mr Elven and had no jurisdiction to adjudicate upon McConnell’s claim, because the issues between the parties concerned the meaning and effect of the supplemental agreement. The supplemental agreement did not contain an adjudication clause. …”
"All the rest will be same as our previous contracts"