David Jewers, 37, told an employment tribunal in Newcastle on Wednesday that he felt "intimidated, patronised, and threatened" by a supervisor who reprimanded him with obscenities.

The father-of-one said he was belting out songs along with the radio at the plant in Sunderland, when he was approached by manager Andy Whitmore who told him he was distracting other workers.

Minutes later, Mr Jewers, from Gateshead, told Mr Whitmore he would "punch his head in" if he ever spoke to him like that again, the tribunal heard.

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But he blamed the outburst on the fact that he had been asked to return to the stressful work soon after he had been off sick with stress for four months.

Mr Jewers said he was assigned to a non-manufacturing section for lighter work until he was medically fit but was soon filling in for an assembly worker.

Mr Jewers, who is seeking damages for unfair dismissal, said: "I was happy in my work and did not believe that I was causing offence or disturbing the fellow workers in my section.

"I regularly sing along with music from the radio on my section and had never been spoken to by any supervisor in this regard.

He was "shocked and offended" when Mr Whitmore told him he had been "distracting the other workers" and that there had been "lots of faults on the line".

Mr Jewers was sacked following an internal investigation which found his outburst to Mr Whitmore amounted to gross misconduct.

Judgement was reserved until a date to be decided.