Chris Barrett is backed by his union

Chris Barrett had been playing a "competitive" game with a former squash instructor when he said he could not walk without a splint, it was claimed.

His dismissal in August 2003 prompted a strike by members of the Rail, Maritime and Transport union (RMT).

The RMT is backing his claim for unfair dismissal, but London Underground (LU) said it acted fairly in the case.

Earlier the tribunal heard Mr Barrett, 30, had been off work for six months with insomnia.

He was fired from his �32,000-a-year job after a surveillance operation by LU caught him leaving a sports centre on 10 July.

My view was that he knew he would get paid contractual sick pay whilst off sick, and had decided to take advantage of it Nigel Holness, London Underground

He had injured his ankle playing football and his managers said he had told them he was unable to walk on it without a splint.

Mr Barrett later said they had misinterpreted his comments.

He said he had been advised to undertake gentle exercise to strengthen his ankle, by a sports injury therapist.

But Nigel Holness, who presided over Mr Barrett's internal appeal, said he was "sweating profusely" which suggested he had been "subject to a strenuous workout".

He told the tribunal: "My view was that he knew he would get paid contractual sick pay whilst off sick, and had decided to take advantage of it by not coming to work when he clearly could have and he had acted dishonestly."

Part-time work rumours

Earlier trains operations manager Hilary Signy told the tribunal she became suspicious about Mr Barrett's sickness because he did not seem to want face-to-face contact.

And she had heard rumours that he had been working in a part-time job and doing "gigs" as a DJ.

When he was stopped at the sports centre, it was the second time in a few weeks he had been off with the ankle injury.

He also failed to attend two meetings with managers, said Mrs Signy.

She said Mr Barrett should have known he was required to attend meetings to discuss his sickness, because he had previously been off sick for nearly six months with insomnia.

She told the tribunal that in July Mr Barrett had said his GP had recommended playing squash as good exercise for his ankle but provided nothing in writing to this effect.

The hearing was adjourned until Thursday.