Mulalley was appointed as the main contractor on a refurbishment project for a housing association in South-East London. Viridis, a specialist window sub-contractor, tendered for the work to replace the windows and doors and was subsequently issued with a number of separate orders from Mulalley. Following termination by Mulalley, Viridis referred a dispute over its final account to adjudication. The adjudicator resigned as a result of Mulalley’s successful jurisdictional challenge, arguing that there was no dispute. Viridis then commenced a second adjudication and Mulalley raised another jurisdictional challenge, contending that the alleged main “sub-contract order” had never been accepted by Viridis and that all works had been undertaken under six separate contracts and not a single one. The adjudicator, having found that he had jurisdiction, made an award in favour of Viridis who then sought to enforce the award when Mulalley did not pay.

At trial, Mulalley maintained its multiple-contract argument whereas Viridis alleged that there was an overarching contract and that the subsequent orders were either works orders placed under it or were variations to it. HHJ Stephen Davies held that the adjudicator’s decision should not be enforced. The court held that:

(i) alleged main sub-contract order, either expressly or by its conduct. The order amounted to separate contracts complete in themselves and could not be viewed as sub-orders or variations under an overarching framework of one contract. Further, the work that was the subject of the dispute was carried out under three different orders so the adjudicator did not have jurisdiction as a dispute arising under more than one contract had been referred to him.

(ii) an adjudicator can decide jurisdictional issues that are part of the substantive dispute only if he is appointed under a contract about which there is no dispute. As the court found that Viridis had never accepted the so-called “main sub-contract order”, the very contract under which the adjudicator was allegedly appointed was in dispute. Further, as Viridis had only advanced a simple final account claim, the issue of whether there was more than one contract was not part of the substantive dispute of the adjudication and therefore went to the adjudicator’s jurisdiction (which he then wrongly decided upon). The court also held obiter that once it had made a final ruling after a full trial that showed that the adjudicator was wrong, his decision could not be enforced, even if the basis of Viridis’s argument had changed.

(iii) (obiter), the adjudicator had not breached the rules of natural justice in the various ways alleged: (i) by disregarding Mulalley’s certificate defence in his decision, as he had considered all of the documents and submissions provided to him; (ii) by addressing the termination issue since Maulalley had raised it as a defence – it was not open to a party to raise a particular issue and then seek to restrict the adjudicator’s ability to decide that issue; and (iii) by deciding what sum was due to Viridis under its final account claim – even if he made an error in the sum, that error was within his jurisdiction to make.