Mr Jewers said he had acted out of character during the incident

David Jewers, 37, was singing A Little Less Conversation for workers when he claimed he was subjected to obscene abuse by supervisor Andy Whitmore.

Mr Jewers, from Gateshead, told an employment tribunal in Newcastle last month he seethed with anger for 15 minutes at the alleged abuse before reacting angrily.

But on Wednesday it was revealed the tribunal ruled against the claim of unfair dismissal, stating that Nissan had followed a reasonable procedure in dismissing Mr Jewers.

He had claimed he sang at work to help him cope with his depression, after being off sick with stress for four months.

The married father-of-two was dismissed from his �26,000-a-year job at the Nissan plant in Washington, Wearside after telling the foreman he would "punch his head in" if he spoke to him like that again.

Tunes on radio

He had told the tribunal the subsequent outburst against his boss was "completely out of character" and a result of his medical condition.

Mr Jewers, a part-time nightclub crooner on the North East club circuit, had been singing along to tunes piped over the radio to workers at the time of the incident in August 2002.

His solicitor, Bryan Slater, had told the hearing: "He deals with it but people who are susceptible to pressure come apart from time to time. He did it in his own way. He sang Elvis songs. He was an Elvis fan."

But Seamus Sweeney, for Nissan, had questioned why "at no stage" had Mr Jewers told earlier inquiries into the incident that his actions may have been the result of his "medical condition".