A new attempt to ban smacking will be launched tomorrow by a cross-party group of MPs, as more than 100 Labour backbenchers demand a free vote on the issue.
MPs, led by Kevin Barron, the Labour chairman of the all-party Commons Health Committee, are attempting to stop parents from smacking their children as a "reasonable punishment". They will table amendments to the Children and Young Persons Bill, due to be debated by the Commons tomorrow, to give children the same protection against assault as adults.
Campaigners said that 111 Labour MPs had signed a private letter demanding a free vote on smacking, with some backbenchers warning they are prepared to defy Government whips if ministers do not back down.
The last attempt to impose a full ban on smacking was defeated in 2004 when a compromise was agreed, tightening the law by outlawing punishment which left physical marks or caused mental harm. But campaigners say they want action to give children protection against all physical punishment.
Mr Barron said: "We must act now to end the legal approval of hitting children. It is the responsibility of Parliament to ensure that the physical integrity and human dignity of every person is respected. The current law allowing so-called 'reasonable punishment' of children is unjust, unsafe and unclear, and must be abolished once and for all."