Amey Wye Valley Ltd v The County of Herefordshire District Council (Rev 1)

Adjudicators’ decisions are enforceable despite errors of fact, law or arithmetic, provided the adjudicator decided the dispute referred and did not re-decide an issue already determined by an earlier adjudicator. The court on enforcement does not correct calculations or investigate the merits of the adjudicator’s reasoning.

Where a single financial dispute is within jurisdiction, an apparent calculation error cannot be severed merely to produce a different result. Severance may be available where distinct parts of a decision concern separate matters, one within and one outside jurisdiction. The scope of an earlier adjudication is determined by the dispute referred and the decision actually made.

The parties were engaged under a ten-year highway maintenance contract incorporating an inflation-adjustment mechanism. An earlier adjudication by Mr Entwistle determined the contractual meaning and effect of VOP3, but expressly did not determine its financial consequences.

A later adjudication by Mr Molloy calculated those consequences and ordered Amey to repay a substantial overpayment to the Council. Amey brought Part 8 proceedings challenging enforceability and seeking declarations that the later decision was inconsistent with the earlier decision. The Council sought summary judgment under Part 7 proceedings. The central issues were whether Mr Molloy had exceeded his jurisdiction, whether an arithmetic error permitted severance, and whether the earlier adjudication prevented repayment.

1. Enforcement and jurisdiction. HDC was entitled to summary judgment for the full amount of the Molloy Decision, adjusted for interest. Amey’s Part 8 proceedings failed. The decision was enforceable notwithstanding errors in the calculations.
2. The court’s task on enforcement was confined to jurisdiction and natural justice. There was no natural justice issue. The court would not conduct a detailed review of the adjudicator’s arithmetic, findings of fact or alleged errors of law. An adjudicator’s decision remains enforceable if the adjudicator decided the dispute referred, even if the decision contains mistakes.
3. A second adjudicator may determine a further dispute, but may not decide again what the first adjudicator already decided. The relevant inquiry is the terms, scope and extent of the earlier reference and decision. Mr Entwistle decided the binding nature and meaning of VOP3. He did not decide its financial consequences. Mr Molloy had jurisdiction to calculate those consequences, including a calculation showing that Amey had been overpaid.
4. The arithmetic error in the Molloy Decision did not justify severance. The dispute was a single dispute concerning the financial effect of the inflation adjustment. Correcting the spreadsheet would amount to correcting an error of fact or arithmetic, not severing a jurisdictionally distinct part. Severance could apply where separate parts of a decision concerned distinct matters, one within and one outside jurisdiction.
5. Remedy (g) in the Entwistle Decision concerned deductions being attempted during that adjudication. It did not prevent a later calculation of the financial consequences of VOP3, or repayment if the calculation showed an overpayment. The Part 8 declarations were therefore refused.

The judgment itself was a first-instance decision concerning enforcement of an adjudicator’s decision and related Part 8 declarations. No appeal history is stated.