Britain should be stripped of its EU rebate for breaking solidarity at the European summit, MEPs have been told.
Joseph Daul, leader of the centre-right European People's Party - from which the Prime Minister withdrew his Tory MEPs on coming into office - said Mr Cameron had acted with no consideration for EU solidarity.
During a rowdy debate of relentless attacks on Mr Cameron, Britain's position was supported by just a handful of MEPs, including Jan Zahadril, the Czech leader of the European Conservatives and Reformists Group, which includes the UK Tory MEPs.
And, to catcalls and jeers, UK Independence Party leader Nigel Farage declared: "We are going to get out of this union - the first EU country to get its freedom back."
But hours of debate focused on how the row with Britain had diverted attention from the need to restore eurozone stability and credibility.
Mr Daul condemned the lack of British solidarity and warned: "The British cheque (the annual rebate on the UK's EU contributions) is now up for question. Tax monies should be spent on someone else rather than compensating selfish nationalism.
"It's time to remind Mr Cameron's governing coalition of its obligations, particularly in terms of financial regulation, for which it even asked for a derogation (exemption)."
The annual rebate, which has reduced the size of the UK's contribution to the EU budget over the past 25 years by billions of pounds, including about £2.7 billion this year, is up for renegotiation soon as part of long-term EU budget plans.
Asked by a British MEP if he was threatening the UK, Mr Daul replied: "There will be no tanks, no Kalashnikovs before Christmas. But I did indeed says that if UK solidarity, as it seems, has been abandoned towards the other 26 (member states), I can't see why the other 26 should make an extra gesture towards the British.
"This is not a declaration of war - it just that solidarity works in both directions."