Senior Labour MPs lead campaign to ban smacking. 50 backbenchers ask colleagues for support. Chief whip urged to hold free vote on 'moral issue'

A fresh parliamentary attempt is to be made to ban the smacking of children, led by senior Labour backbenchers, including the chairman of the all-party health select committee.

Nearly 50 backbenchers are writing this week to fellow Labour MPs asking them to support a free vote on the grounds that treatment of children is a moral issue, and should not be subject to a government whip. Campaign leaders have already met the government chief whip, Geoff Hoon, to discuss the possibility of a free vote.

MP Greg Pope: "It is simply wrong that a form of violence that would lead to criminal charges if it was inflicted on an adult is lawful so long as a child is the victim."

Hoon told the MPs he would gauge the mood in the parliamentary Labour party before replying. Campaigners expect to secure support from more than 100 Labour MPs in favour of a free vote.

Labour MPs including Kevin Barron, chairman of the health select committee, and former whip Greg Pope plan to propose a ban by tabling an amendment to the children and young persons bill, due to go to the Commons from the Lords next month.

In their letter to MPs, the 50 backbench opponents of smacking argue they should not be put in the "intolerable position" of either having to defy the party whip or not support the principle of equal protection from violence for children. They argue that a free vote would satisfy the concerns of opponents of smacking, and allow ministers to put some distance between themselves and the issue.

The last time a ban was voted on in the Commons, in 2004, 47 Labour MPs rebelled and voted for a ban. In a bid to quell the rebellion ministers promised a government review. That review, completed by the children's minister, Kevin Brennan, last October, ended by favouring the retention of the current law which allows children to be reasonably punished so long as the violence does not amount to actual bodily harm. In practice this "reasonable chastisement" allows parents to hit children so long as they do not cause severe bruising.

The government review claimed the issue was receding as younger parents are less likely to smack than older parents. Ministers were in reality worried that a ban would go against the grain of public opinion and lead to charges that ministers were running a nanny state.

An Ipsos Mori survey for the review of nearly 2,000 parents found more than half had smacked their children and 70% thought it right to retain the deterrent. Teachers and carers are not allowed to hit children.

Some Labour MPs say they will rebel if the issue is made subject to a whip.

Pope, one of the campaign leaders, said yesterday: "It is simply wrong that a form of violence that would lead to criminal charges if it was inflicted on an adult is lawful so long as a child is the victim." He said nearly half the 27 EU member states had a ban on violence to children.