Mandatory jail terms for offenders caught twice with a knife are poised to be introduced despite a deep coalition split over the move.
Conservative ministers will abstain in a Commons vote on the measures next week because they cannot support proposals that have not been agreed on by both governing parties.
But Tory backbenchers are free to back the Bill amendment that would bring in the reform and Labour has previously said it is "sympathetic" to move.
That could mean the proposal wins enough support to become law in the face of fierce Liberal Democrat opposition.
A Government source said: "The Conservatives have always made clear we want to do more to tackle knife crime. The Commons will vote next week on an amendment to jail people caught carrying a knife on more than one occasion.
"Conservative ministers support these plans in principle. But because this is not an agreed coalition policy, they will abstain in Tuesday's vote.
"However, other Conservative MPs will be free to vote as they wish and these new powers stand a good chance of becoming law."
Metropolitan Police Commissioner Sir Bernard Hogan-Howe has backed the automatic sentencing proposals while Lord Chief Justice Lord Thomas, the most senior judge in England and Wales, has called for an urgent review of sentencing for youths carrying knives.
But Liberal Democrats accused the Tories of seeking to exploit the death of teacher Ann Maguire in a Leeds classroom for political gain.
Deputy Prime Minister Nick Clegg fears that mandatory sentences could lead to innocent peopled being jailed and risk turning the "young offenders of today into the hardened criminals of tomorrow".
A senior Lib Dem source said: "The Liberal Democrats have been clear from the outset that we do not agree with these proposals. We set out our position in May.
"As a result, all Liberal Democrat MPs, whether ministers or backbenchers will be voting against the amendment - the parliamentary party is united on this.
"The key to reducing crime is to focus on what works - firm, practical solutions that address the root causes of crime and stop people offending in the first place.
"Under this Government, crime is at its lowest levels since independent records began.
"We believe in giving judges the flexibility to use their expertise and judgement, based on the facts of each case. Prison is often going to be the right option and violent offenders who are a danger to the public ought to be behind bars, but that should be for judges to decide."