In response, all 19 Lib Dem ministers are now expected to oppose planned Tory changes to electoral boundaries in a revenge move.

Speaking to BBC’s Newsnight last night, deputy Lib Dem leader Simon Hughes said, "What do you expect us to do if the Tories say they can't deliver, what do you expect us to say - say 'this is all very sad, I'm sorry about this'?

“You can't allow a coalition to go ahead if both sides don't deliver and the message to the Tories is they must deliver and, because they haven't, we can't do the deal on boundary changes."

Mr Hughes words come after both Nick Clegg and senior Tories said that there is still unity between the coalition partners. Earlier this year Mr Clegg claimed that there was no link between the two issues, whilst Tory MP Nick Boles added yesterday that the two parties would quickly put their differences on the issue behind them.

Mr Boles said, “We've not been able to deliver one part of that agreement. I think it's very regrettable that that's the case and I think it's very regrettable that they've decided, therefore, not to deliver another part of the agreement.

"But that's life - we'll get beyond it, we'll put it behind us. There are far more important issues to work on."