UK   All forms of physical punishment of children beyond a 'minor smack' are to be made illegal under plans being drawn up by Downing Street and the Department for Education.

For the first time senior Whitehall sources have told The Observer that the Government is now willing to look at reforming the defence of 'reasonable chastisement' for people who hit children.

The reform of the Victorian law will be the first step towards an almost total ban on smacking, although the Government will make clear it has no desire to criminalise parents who give their child a quick smack at moments of frustration or to keep them out of danger.

'We are sympathetic to looking at reforming the reasonable chastisement defence in a way that catches those who assault their children and then use this defence,' a source close to Charles Clarke, the Education Secretary, said. 'But we do not want to make criminals of the mother in Sainsbury's whose child is about to run into the street and they give them a smack across the back of the legs.

'We do not want to be seen as the nanny state, so we will not be supporting any move to ban all smacking. But we do see that the law could be reformed. 'It is a very complex area and we will be seeing if there is a legal form of words that allows us to draw the distinction between the two types of child punishment.'

The Government is very nervous of the debate on smacking and has in the past said it has no plans to change the law for fear of being accused of meddling in family life.

It was not mentioned during the launch of the Child Protection Bill last week despite the Bill being described as a comprehensive document dealing with all child abuse matters.

But moves by backbench Labour MPs to amend the Bill, at present going through Parliament, so that smacking faces a complete ban have caused a rethink. Officials signalled that, if an amendment was laid which fell short of a complete ban but did call for the abolition of the reasonable chastisement defence, then the Government would allow a free vote on the issue.

This would then almost certainly be passed, most probably in June, before becoming law next year. Officials from Number 10 and the Department for Education are now discussing how the law could be changed.

Bringing children under the adult law could make it an offence to hit children except in self-defence. Legal advisers to the Government will be told that they must ensure that millions of parents are not criminalised at the stroke of a pen.

David Hinchcliffe, the Labour MP for Wakefield and chairman of the House of Commons health committee, is now planning to table such an amendment. Although he told The Observer he supported a complete ban, he could understand the position of the Government.

'The end of the reasonable chastisement defence would mark a fundamental shift in the way we think about what is permissible when it comes to children, and that has to be welcomed,' he said.

'Abolishing the defence of reasonable chastisement would send the message that we have to change our attitudes when it comes to matters of child discipline away from the physical approach.'

Hinchliffe said courts often allowed the defence of reasonable chastisement in cases which child support groups said amounted to assault. He said that the 'turn a blind eye' to the issue attitude led to the death of at least one child a month. Parents or carers who had appeared in court or had defended their actions against their children by the present defence often went on to do more harm.

'What I am worried about is what the parent who gives their child a wallop in Tescos is doing when they get home,' Hinchliffe said.