Mutinous Tory backbenchers gave Prime Minister David Cameron a big headache over the EU today.
More than 40 Tories pledged to defy government whips and vote for big cuts in Britain's cash contribution to the EU budget.
A rattled Mr Cameron accused Labour of "rank opportunism" for preparing to march into the voting lobby last night alongside the Tory rebels.
During noisy exchanges at Question Time, opposition leader Ed Miliband insisted that Labour was in favour of a "real-terms reduction" in the EU budget.
Mr Miliband said the PM had "thrown in the towel even before these negotiations have begun."
A throaty roar of delight arose from the Tory benches when Conservative MP Andrew Stephenson urged Mr Cameron to use the veto if he failed to get a "good deal" in EU budget negotiations.
Mr Cameron replied that he was "quite prepared to use the veto," but it was in Britain's interests to try to get a deal. At best, he wanted a cut in the budget. At worst, it should be frozen.
The government motion which provoked last night's Tory rebellion proposed a maximum inflation-linked rise of around 2 per cent in Britain's contribution instead of the EU Commission's suggested "substantial" increase.
Rebel Tory MP Mark Reckless declared that he wanted to make sure that the EU also "feels some of the pain" at a time when his constituents were facing "massive cuts."
Westminster's three Plaid Cymru MPs refused to support the rebel Tory amendment.
Carmarthen East MP Jonathan Edwards warned it would lead to even bigger cuts in Wales, slashing EU funding for the nation's poorer areas and farmers.
Mr Edward's said he would not support "crazy right-wing Conservatives."