Britain should be stripped of its EU rebate for breaking solidarity at the European summit, MEPs were told today.
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."
Former Belgian prime minister and Liberal MEP Guy Verhofstadt refused to speak English to deliver his speech on the summit, saying: "I shall speak my native language today because I don't think English is a very appropriate language to use."
But he reverted to English at the end to say: "I think that after a few nights David Cameron will come to the conclusion that he made the blunder of a lifetime.
"If Cameron really wanted to obtain additional guarantees for the City of London, he really needed to be at the negotiating table. Why? Because in politics there is one golden rule: you only walk away from the table if you know the others will come to get you back."
It worked for Margaret Thatcher in her tussles with the then leaders of France and Germany, he said, but not this time.
Mr Verhofstadt warned: "When you are invited to a table, it is either as a guest or you are part of the menu. That can happen."
And he added: "This selfish British strategy of protecting the City is one we cannot tolerate any longer."
But Mr Zahradil insisted Mr Cameron was no different from other key leaders: "What he did was just a defence of his country's national interest, in the same way as (French president) Sarkozy and (German chancellor) Merkel did, because they pretend they were speaking on behalf of Europe, but they were speaking on behalf of themselves."
Mr Zahradil told the chamber: "You have no reason to criticise the United Kingdom or its Government."
Mr Farage said: "David Cameron did what he had to do - he was forced into an impossible position, but he gained no concessions whatsoever.
"We simply have no friends in the room: they want our rebate ... the European debate has now started in earnest and Cameron does not know what he has unleashed."
The Ukip leader said the British mistake was to believe that it needed influence in Europe and that "we can change things".
Mr Farage said "We go on paying you £50 million a day, we have helped your bailout fund even though we are not in the eurozone, we give you 80% of the fish stock that swim in our waters, we have applied every European rule - all that to gain influence.
"And when a British Prime Minister goes to a summit with a very modest proposal to protect a British industry, a snarling Sarkozy tells him where to go and he is without a friend in the room: some influence!"
Mr Farage continued: "Well, you've decided to go off on the Titanic and we are in the lifeboat - but now we're threatened with a bow wave: financial markets legislation is going to be imposed on Britain and we will have no influence over it whatsoever.
"We are going to get out of this union - the first EU country to get its freedom back - and then we'll have influence in the world while you lot head for disaster: it is going to happen."
Senior Tory MEP, Timothy Kirkhope, urged calm: "Now is not the time for hysteria, swagger or melodrama on any side. We should analyse events coolly and calmly."
He said the UK wanted a solution to the eurozone crisis "but not at the expense of the single market because competitiveness remains the key".
He went on: "We are still a full member of the European Union and will remain so. We have major trading currency to protect. It make sense to strengthen the eurozone rules - but it makes little sense and seems unfair not to protect the City of London."
Leader of Britain's Labour MEPs Glenis Willmott accused Mr Cameron of "trying to save his friends in the City and not (save) British jobs and growth".
She said: "Friday was not a good day for Britain and not a good day for diplomacy. Mr Cameron has left Britain high and dry. This was a catastrophic failure of his leadership. and if there is one party standing up for Britain, it is the Labour Party."
Ms Willmott said the Liberal Democrats had to take responsibility too, saying: "They have let this country down big time."
Martin Callanan, leader of Britain's Conservative MEPs, said: "Bullying and threats did not work on Mr Cameron last week - and they won't work on his MEPs this week.
"Clearly the architects of this move to fiscal union feel wounded by the UK's veto - so they lash out.
"They reach for the nearest, the most obvious weapon that comes to hand - and of course that is the rebate."
He went on: "But make no mistake, it is not up for negotiation. Our net contribution is more than £6 billion in spite of the rebate - and unlike Labour, Conservatives are not for handing any rebate back.
"Unless he wants to see another veto, Mr Daul should reconsider this rash threat, stop trying to menace us and concentrate on containing the euro crisis."