Senior Conservative backbenchers are threatening to mount their biggest rebellion since the general election in protest against the Government's plans to reform the House of Lords.
The revolt has spread to all sections of the party, provoking a fresh crisis for Coalition unity. The scale of the backlash forced ministers to hold emergency talks designed to salvage the policy being championed by the Liberal Democrats.
The Government's reform plans are due to be published next Tuesday, with key votes due before the Commons rises in mid-July. The rebels are expected to mass behind a call to have no limit on the time spent discussing the reform Bill – which would raise the prospect of opponents dragging out the debate indefinitely.
Rebel ringleaders say Tory opponents of the Bill now far outnumber the 81 who defied the Whips last year to vote for a referendum on Britain's place in the European Union. They told The Independent yesterday that feelings had been heightened by the Liberal Democrats' decision to abstain in a Commons debate last week calling for an investigation into the conduct of Jeremy Hunt, the Culture Secretary.
One said: "People are spitting blood about being asked to vote for reform of the Lords. There are so many unanswered questions about what happens when you start unpicking our constitutional settlement." Another Tory source said: "It is not just the 'usual suspects' who are raising their concerns with the Whips. Sensible and thoughtful people are getting involved."
The Cabinet will meet shortly to finalise its proposals for the Lords to become 80 per cent elected. They have had to adjust the proposals to tackle the objections of Tory MPs that a mainly elected Lords would threaten the supremacy of the Commons.
The planned Bill will now spell out that the will of the Commons ultimately prevails if there is deadlock between the two Houses.
However, if it is ultimately shelved because of a threatened parliamentary logjam, that will store up other problems for David Cameron. At that point the Liberal Democrats could threaten to block proposals to cut the number of parliamentary boundaries by 50, which is a Tory priority.
Labour's attitude to the reform plans could be crucial. The party backs a fully-elected second chamber and could be tempted to back Tory rebels'support for extended scrutiny of the legislation.
Plumbing and patio doors get launch in house
The House of Lords has been used to launch a bizarre range of comm-ercial products including a valve to stop your toilet overflowing and patio doors over the past two years.
If a company has connections with a willing peer it can book some of the grandest rooms in London for its launch party.
The House of Lords rules do not forbid such launches as long as the peer sponsoring the event has no financial connections to the company. But companies are not supposed to benefit financially, even indirectly, from such events.
One product that had a Lords launch was an "easy fit valve" designed to stop toilets overflowing which was created by Watertight International and sponsored by Lord Redesdale. The life peer became a non-executive director of the firm a month later. He said there was no link between the appointment and the launch.
Then there was the launch of a set of "environmentally friendly" sliding doors, sponsored by Lord MacKenzie. The peer said he had no financial interest in the company, that its director was a friend and the event was not a launch but a way of generating interest in a "green concept". He said he checked the rules beforehand.