Liberal Democrats are demanding an increase in the age of criminal responsibility from 10 to 14, setting them on a collision course with the Tory right who believe the coalition is already in danger of looking soft on crime.
Children under 14 would be kept out of the criminal courts and be dealt with instead by panels of experts, as part of a Lib Dem "key policy" to be officially adopted next month. It is certain to reopen the debate about serious cases such as the murder of toddler James Bulger and the case of two brothers from Edlington, aged 10 and 12, who were given indefinite sentences last year after torturing two young boys.
The policy was branded "retrograde and absolutely bizarre" by one Tory MP, Philip Davies. "We have seen some horrendous crimes by people under 14 who knew perfectly well what they were doing," he said.
It risks aggravating tensions over criminal policy, which have seen Kenneth Clarke, the Justice Secretary, dubbed the "sixth Lib Dem in the Cabinet" for his emphasis on rehabilitation over the "prison works" stance favoured by Tory traditionalists.
However, Lib Dem strategists are anxious that the party is able to demonstrate influence on the Government right up to the 2015 general election. They will use their spring conference in Sheffield to state their intention to fight the next election campaign "with no preference for potential future coalition partners". They will also lay public claim to coalition policies that are Lib Dem in origin, and point out where they have been forced through by Conservatives.
The new youth justice policy, backed by Lib Dem ministers, will be set out at the conference by Tom Brake, the party's home affairs spokesman. Before the election Nick Clegg criticised Labour's record for "criminalising a generation of our children". He highlighted figures that showed the number of 10- to 12-year-olds convicted rose by 87.2 per cent between 1997 and 2007. "We need to see innovative approaches that ensure children make amends to their victims and put things right, rather than immediately criminalising them," Mr Clegg said.
The Lib Dems argue that it is difficult to defend England and Wales being out of step with countries such as Italy, New Zealand and Spain, where the age of criminal responsibility is already 14. In Scotland, it will shortly rise from eight to 12. "We need to protect our children from making mistakes and should not expect vulnerable children to make judgements and decisions that many adults struggle with," the policy document, Taking Responsibility: Policies on Youth Justice, says.
Specially trained panels would assess why a child committed a crime and tackle the causes, including educational needs, mental health issues, abuse or neglect. "The policy proposals on youth justice look at the tackling of youth crime and reoffending in the round," a senior Lib Dem source said. "Our Conservative partners may not agree on all of this, but this policy paper puts us in a good position to build on where we agree and to convince them of the merits of our proposals where we do not yet agree."
Under Labour, the Ministry of Justice rejected calls for a change in the age level, but since then there has been renewed pressure from groups including the Law Society and Barnardo's.
Additional reporting by Kimberly Middleton