Vince Cable waded into the row between Nick Clegg and David Cameron today, saying he was in "complete solidarity" with his party leader.
The business secretary insisted there was no chance for the Tories to pass their boundaries review because the Liberal Democrats had enough votes with Labour to stop them in the Commons.
"We've taken the view that if we can't get the support of the Conservatives to pursue House of Lords reform we don't see why we should support constitutional change, which they are very anxious to have," he told his local paper, the Richmond and Twickenham Times.
"Obviously if there's a vote then there's a vote, but I think the Conservatives alone don't have enough.
"There are a lot of Conservatives themselves who are unhappy with the boundary changes, but even if they all voted for the changes there are not enough votes to get it through.
"I will be 100% supporting Nick Clegg's suggestion. We maintain complete solidarity on this issue."
Despite several instances in which Clegg expressed his support for the plans, Cable suggested he was always against the review today.
"The impression I have is that those people in my constituency prefer to keep the boundaries as they are. They don't want to be hacked up and be combined with bits of Hounslow and lose bits of their identity," he said.
"The Liberal Democrats have made it very clear we will be opposing changes and I think Labour will be opposing the changes, so I think it's very difficult to say they will proceed.
"I think essentially the likely outcome now is the status quo. I think most people would prefer that, and it makes life easier in terms of campaigning for both of the borough's sitting MPs because we are campaigning in areas we know and where people voted for and against in the past."
The comments come amid signs the public blames the Conservatives for the division in the coalition.
A YouGov survey found 44% of people believe the Liberal Democrats had kept to their side of the coalition bargain, against 32% who said they have not.
That compares to just 30% who said the Tories have stuck to their side of the bargain, while 51% disagreed.
Fifty-two per cent of respondents told YouGov the Tories gained more from the coalition, while just 23% believed the Liberal Democrats benefitted more.
David Cameron issued a robust rebuttal to Clegg yesterday, when he insisted the deal during the coalition talks exchanged the AV referendum, rather than Lords reform, for the boundaries review.
"There's a fundamental disagreement here in that I profoundly believe that the link was between the AV referendum that we promised to deliver and the boundary changes," the prime minister told LBC radio yesterday.
"Now Nick takes a different view, he's entitled to do that."
The fundamental difference in Cameron and Clegg's memory of the coalition agreement raises serious questions about their ability to work together over the next three years.
On Monday, Clegg said: "The Conservative party is not honouring the agreement to Lords reform and as a result part of our contract has been broken.
"I cannot permit a situation where Tory rebels pick the part of the contract they like. Coalition works on mutual respect, it is a reciprocal arrangement.
"When, in due course, parliament votes on boundary changes for the 2015 election I will be instructing my party to oppose them."
The development suggests the 91 Tory rebels may have made a mistake in opposing Lords reform, at least at a strategic level.
The rebellion killed off the prospect for a boundary review and lost the Conservatives at least 20 seats at the next election. They seem to be losing the battle of public opinion as well.
Forty-three per cent of respondents to the YouGov survey wanted the coalition to split immediately, with many of them favouring an immediate general election.
Sixty-six per cent backed an immediate election, against 22% who would be happy to see a minority Tory administration.