The watchdog responsible for MPs' pay and perks is to set out its plans to introduce an 11% pay rise amid threats that the controversial proposals could lead to the organisation being axed.
Opposition leader Ed Miliband has called on David Cameron and Nick Clegg to accompany him to a meeting with the Independent Parliamentary Standards Authority (Ipsa) to demand it halts the wage hike.
The Prime Minister has yet to agree to the move but yesterday issued a v eiled threat to abolish Ipsa if it presses ahead with the planned rise after the 2015 general election, insisting it was "simply unacceptable" that Members' salaries would increase increasing by £7,600 to £74,000.
Ipsa officials have remained defiant since the possibility of a siginificant hike in pay emerged this year and the organisation's chief executive, Andrew McDonald, has insisted the public have a "more sophisticated" view of the proposed package than they are being given credit for.
"T his is an issue where the public has a more nuanced, and split, opinion than the reactive howls of 'outrage' from some commentators and politicians," he wrote on Ipsa's website.
" The package we will announce on Thursday will, taken as a whole, not cost the taxpayer a penny more," he added. "That message has not been heard in the hubbub of the last few days."
Ipsa is planning a tougher-than-expected squeeze on MPs' pensions in a bid to cancel out the £4.6 million cost to the public purse. A £ 2.5 million saving by downgrading the final salary scheme to career average - matching the rest of the public sector - had already been proposed alongside a crackdown on various perks.
But MPs are acutely aware of the potential damage such a pay rise would cause with the public at a time when many workers are facing redundancy or pay cuts and freezes.
Mr Cameron suggested yesterday that abolition of Ipsa is on the table if it pushes ahead with the plans.
"First, the idea of an 11% pay rise in one year at a time of pay restraint is simply unacceptable," he told MPs.
"Secondly, Ipsa do need to think again and, unless they do so, I don't think anyone will want to rule anything out. No-one wants to go back to MPs voting on their own pay but we have got to have a process and an outcome that can build public confidence.
"Third, in my view, I think this should all be accompanied with a cut in the cost of politics."
The recommended pay rise will be subject to a statutory review by Ipsa after the 2015 contest, and Downing Street said the process should be allowed to run its course.
But Mr Miliband has called for urgent action and wants the three main Westminster party leaders to meet Ipsa chairman Sir Ian Kennedy immediately "to make cl ear our view that we cannot go ahead with the current proposition".
In a letter to Mr Cameron, the Labour leader said: "The public expect us to resolve this now and not wait until 2015. It only undermines confidence and trust in our political system if the uncertainty about MPs' pay is allowed to continue."