A head teacher suspended then cleared of slapping a pupil is unlikely to win compensation because it would be difficult to prove mental or physical distress.

Marjorie Evans was seeking reimbursement after being convicted, in 2000, of hitting an unruly boy, aged 10, at St Mary's Junior School in Caldicot.

She overturned the court verdict on appeal, returned from 18-month suspension and now wants to sue her Monmouthshire local education authority for stopping her working.

Prince Charles wrote a letter of support to Mrs Evans

The National Union of Teachers, which backed her all the way, said she must prove the authority was unreasonable and that its behaviour caused mental or physical distress.

The union said it felt proving the authority's unfairness would be easy but that it could not provide any doctor's notes to show the knock-on affect on Mrs Evans' health.

"That's where the claim falls down. She was forced to endure an abnormally lengthy investigation," said NUT Wales officer David Evans.

Ostracised at home

"It is to her credit that she remained a stoic and strong person. Marge never needed treatment and she had support throughout and came through this with flying colours.

"We are unable to show that she suffered psychologically or physically so there is no peg to hang the compensation claim on."

It means the head teacher is unlikely to be financially reimbursed despite at one time being ostracised from some quarters of the community.

• Mrs Evans was suspended after allegedly slapping an attention deficit disorder sufferer in September 1999 following a confrontation.

• At court in July 2000, was convicted of assault but claimed he had tried to punch and head butt her and that he was a danger.

• In September 2000, she won her legal appeal and awaited her return to work but was barred again by education chiefs pending further mistreatment allegations.

• They came to nothing when Gwent Police decided not to press charges in October 2000, but the education authority maintained the suspension.

• In February 2001, she began High Court action to return to work as she again rejected the fresh claims at a disciplinary hearing.

During her ordeal, Mrs Evans remarked the process of fighting her school governors and local education authority in Monmouthshire and at the High Court, London, took a took a big mental toll.

Mr Evans of the NUT said a lesser person may have suffered a breakdown.