Conservatives and Liberal Democrats are at loggerheads over proposals to tighten up the law on knife crime.
Justice Secretary Chris Grayling wants to bring in an automatic six-month jail term for anyone convicted of a second crime involving a knife.
But the chief secretary to the Treasury, Danny Alexander, is concerned that the move would be expensive and put too much pressure on prison places.
A leaked letter from Mr Alexander to Nick Clegg, published in the Daily Mail, says:
‘It is very hard to see how it could be afforded. The Treasury does not support this amendment and I am not willing to clear it."
More top news
Three men have been arrested in Sweden on suspicion of taking part in a rape that was streamed live on Facebook.
An 11-year-old girl has died in a three-car motorway crash.
They wanted it - all power to British courts. Now they've got a taste of what it means. And they might not like it.