By politics.co.uk staff
David Cameron and Nick Clegg have formally agreed to go to war in the Commons over boundary changes while keeping the rest of the coalition intact.
The prime minister announced the move to Cabinet in this morning's meeting, No 10 said.
Yesterday's agreement, which came before Lib Dem ministers in the Lords combined with Labour peers to defeat their Conservative colleagues, was witnessed and minuted by Cabinet secretary Sir Jeremy Heywood.
The pair agreed to "set aside" the Cabinet's collective responsibility, Downing Street explained.
Liberal Democrats in government are determined to defeat the Tories' planned boundary changes, which Nick Clegg's party now oppose after Tory backbenchers made Lords reform impossible.
It had been thought that the Conservatives could still win the critical vote on the issue, which must come before the autumn, with the help of nationalist and Northern Ireland MPs.
Tory hopes of gaining a boost of around 20 extra MPs as a result of the redrawing of the electoral map at the next general election seem to be fading, however. Reports suggested the SNP was unwilling to support the Tories on the issue.