Anthony Ratcliffe says he was subjected to a regime of contempt and isolation by the head at Sageston county primary school, near Tenby, Dyfed.

To his acute embarrassment, she once tricked him into handing a gift-wrapped chocolate penis to a retired spinster, a former teacher.

Mr Ratcliffe suffered two mental breakdowns at Sageston, despite no previous history of mental illness. Unable to teach again, he is now working as a self-employed kitchen-fitter.

The Association of Teachers and Lecturers, which represented Mr Ratcliffe, says he faced cumulative difficulties. He was never even given a set of keys to the school, for example.

He was not on first-name terms with the head, Joan Morris, who was said to have objected to Mr Ratcliffe’s wife helping to put up classroom displays.

A statement from the union says: “It was alleged that from the first day Mr Ratcliffe arrived at Sageston he was treated with contempt by Mrs Morris, who had taught for many years at the school and had recently been promoted to headteacher.

“It was alleged that she refused to listen to most of Mr Ratcliffe’s suggestions, or to give him any of the normal responsibilities of a deputy headteacher.”

Dyfed County Council, which has now been broken up into separate authorities, was accused of failing to protect Mr Ratcliffe. After his first breakdown he was sent back to Sageston where, he says, his ordeal continued.

Despite paying #163;101,028 to Mr Ratcliffe, the council does not accept there was negligence on its part or on the part of the head. It blamed inherent personality problems for his breakdown.

Dyfed does, however, accept that he was duped into giving the chocolate penis - to a woman he scarcely knew - although it denies he was told to deliver it with the words “I hope you enjoy a nibble this Christmas”.

Dyfed also accepts that, at the same Christmas party, a bottle of brandy brought by Mr Ratcliffe was re-labelled “Randy Brandy”.

The ATL says it is getting mounting complaints about workplace bullying on its stress helpline.