MPS look set to get a £7000 bumper pay rise this autumn after No 10 signalled the Prime Minister, who has consistently opposed the increase, could now do little if anything to stop it.

The Independent Parliamentary Standards Authority said that the increase - 10 per cent above inflation - would happen in September, just four months after the new Parliament was formed, unless "new and compelling" evidence emerged over the summer. A consultation ends on June 30.

But it appeared David Cameron would not seek to produce such evidence with his spokeswoman, when asked about the planned pay rise, saying representations had already been made and explaining: "Throughout this process and debate the PM has been clear he does not approve of the proposed increase. Ultimately, it is up to Ipsa as an independent body to decide MPs' pay and for them to make their determination."

Before the General Election, when the pay rise was first mooted, such was the strength of opposition to it that there were suggestions of scrapping Ipsa and creating a new body.

Asked if the PM could simply forego his £7000 and give it to charity, his spokeswoman pointed out how Mr Cameron had instigated a five-year pay freeze for all Cabinet Ministers.

Asked if such a pay rise for Westminster's 650 MPs would be regarded as a slap in the face by public sector workers, who have seen their pay frozen, she replied: "The PM has been absolutely clear he does not agree with this."

The setting of MPs pay was taken out of the hands of politicians in the wake of the 2008 expenses scandal.