Bouygues purported to determine Dahl-Jensen’s employment and Dahl-Jensen left site. Dahl-Jensen issued a notice to adjudicate claiming sums for additional works and the cost of delay and disruption. The Adjudicator made a net award in Dhal-Jensen’s favour, after he had regard to the sums he found due in respect of the parties’ individual claims and taking account of the sums previously paid. However, in calculating these sums, the Adjudicator had taken a gross sum that included the retention and deducted from it the sums paid during the subcontract which excluded the retention. The effect of this was to release the retention to Dahl-Jensen when it was not yet entitled to it under the terms of the subcontract.

It was common ground that the claims did not include a claim for the release of the retention monies. The Judge held that the Adjudicator plainly made a mistake but it was a mistake in the calculations on the disputes that were referred to him and therefore within his jurisdiction. It was not a mistaken decision to deal with or purport to deal with a dispute. The Adjudicator did not determine that Dahl-Jensen was entitled to the release of the retention but rather the effect of the decision was to award the retention money to Dahl-Jensen. Therefore, the decision was enforced.