Cameron given rough ride by backbench critics

David Cameron last night promised to reform the new body in charge of MPs' expenses unless it improves its performance by next April.

MPs have complained that the Independent Parliamentary Standards Authority (IPSA) is bureaucratic and slow in reimbursing them, and last night Mr Cameron told his backbenchers that it was not performing well enough. He added that the curbs on second-homes allowances – which force new MPs to rent properties in London – were "anti-family". He declared: "There needs to be a better system in place by next April. Otherwise, it will have to change."

The Prime Minister's comments came just hours after the public-spending watchdog refused to sign off the House of Commons accounts because of concerns about the "regularity" of payments to MPs.

Amyas Morse, the head of the National Audit Office, said he could not confirm the validity of £13.9m of claims because he was unable to inspect supporting documentation. The money was paid mainly in the period between the eruption of the expenses controversy in May 2009 and the general election.

At last night's meeting, Mr Cameron was also forced to fend off accusations that the "Lib Dem tail is wagging the Coalition dog", particularly because of growing disquiet about the "soft" sentencing policy announced by Kenneth Clarke, the Justice Secretary. Mr Cameron insisted that the Coalition was working well and that Tory MPs could be proud of its achievements.

But Peter Bone, a Tory right-winger, said yesterday the Coalition should not continue until 2015 as Mr Cameron and Nick Clegg envisage. "I accept we need a Coalition Government until the economic crisis is over and we have dealt with it but that might be done within the next two years," Mr Bone told BBC Radio 4's Today programme. "Then I see no point in the Coalition Government at all."