The Claimants, Axis M&E UK Ltd and Axis Plumbing NSW PTY Ltd (“Axis”) were engaged by the Defendant, Multiplex Construction Europe Ltd (“Multiplex”) as M&E Sub-Contractors for a residential development in Kensington. A dispute arose concerning the valuation of Axis’ work and the sum due to them pursuant to their interim payment application.  An adjudication took place under the Scheme for Construction Contracts (“Scheme”).

In the Adjudicator’s decision, the Adjudicator made an error in the calculation of the sum payable which resulted in no sum being due to Axis.  The error was explained to him and, when corrected, the decision was amended so that Multiplex had to pay Axis £654,119.65. Multiplex contested the amendment arguing that the original sum (of nothing payable) was binding on the Parties and therefore outside the slip rule which is incorporated at paragraph 22a of the Scheme.

Mr ter Haar QC held that the important starting point was to consider the dispute that had been referred to the Adjudicator and which was therefore the dispute that he had to decide.  Relying on ROK Building Ltd v Celtic Composing Systems Ltd [2009] EWHC 2664 (TCC), he accepted that the court should consider the context of dispute that was referred to the Adjudicator.  In Mr ter Haar QC’s view, the Adjudicator had understood this task and there was no suggestion that he had made any error when reaching his decision.

Moving on, the Judge noted that what was unusual about this case was whether the Adjudicator was correct to not only correct the principal sum but also award interest and reverse the Order as to payment of his fees.  Acknowledging that this situation had not come before the Court, he considered Gannet Shippling Ltd v East Trade Commodities Ltd [2001] ALL GR (D) 74 which concerned similar clerical issues. Noting that Gannet was an arbitration not an adjudication he explained that there was no “relevant distinction” between the two.  Therefore, he found in favour of Axis.

This case is novel because it demonstrates that the slip rule can result in a change to the sum payable and include interest.  Whilst usually the slip rule is considered for typographical errors, this case demonstrates it can extend to arithmetical ones too.