Multiplex QC says manager acted reasonably over disputed valuation as Wembley trial draws to a close.

Multiplex yesterday closed the Wembley trial by denying allegations of "trickery" and pouring scorn on Cleveland Bridge's attitude to a valuation figure at the heart of the dispute.

In his closing statement to the four-week trial, Roger Stewart QC said that Multiplex UK head of construction Matt Stagg had acted reasonably in refusing to include the £32.66m valuation for CBUK's work up to 15 February 2004 in a supplemental agreement.

He said: "Stagg was saying: ‘I can't have [the £32.66m figure] in the agreement because if it goes in the agreement it can't be changed later if we need to claw back other money in the event of a disaster scenario.' That's completely incompatible with the type of trickery being alleged by CBUK."

CBUK argues that the agreement, which Multiplex has refused to honour, was final and binding and related to a £32.66m figure which had been verbally agreed.

But Stewart said that CBUK had demanded the figure even though Multiplex had never agreed to it. He caricatured the situation over CBUK's demand for the money as: "Will you pay me £5? - No. - Will you write down that you agreed to pay me £5? - No. - Well we've agreed on the figure anyway."

In a series of exchanges over variations to the landmark arch which CBUK erected at the stadium, Stewart also argued that the contract between CBUK and Multiplex was for on-site erection but not for assembly of the steelwork.

In a dramatic exchange between Stewart and Justice Jackson, the judge suggested that Multiplex had acted hastily in kicking CBUK off the project and replacing the firm with Hollandia.

Jackson said: "A possible analysis may be that the court would be saying not that you should have reached agreement [with CBUK] but that you would have reached agreement. Switching to Hollandia was a disaster for Multiplex and led to a loss of more than £100m."

Stewart replied: "On the other hand we got the roof up, and Ashley Muldoon had serious doubts about CBUK's ability to do the job."

Jackson then said: "It may be that if matters were explored more thoroughly Multiplex would have stuck with CBUK but brought in Hollandia to help with the roof."

Stewart later argued that Multiplex had the right to value the work done before 15 February 2004, but that CBUK had always expected the matter to end in arbitration.

"Multiplex's position was always that it was entitled to do the valuation. CBUK's position was that it would go to arbitration… and end up in a trip to St Dunstans House."

St Dunstans House is home of the construction and technology court in the Royal Courts of Justice, where the trial is taking place.

Justice Jackson is expected to give his verdict on the case on June 5.