Tony Blair will get "smashed" by an overwhelming 'no' vote in a referendum on the planned EU constitution, a leading Eurosceptic has claimed.
Could a referendum campaign prompt more scenes like this?
Dominic Cummings, formerly of the anti-euro No campaign, is already talking to senior business figures and hoping to form a new campaign group.
Meanwhile pro-European groups are getting ready to fight their corner now a referendum has been announced.
Mr Blair told MPs on Tuesday people would get a vote on the constitution.
The news prompted Vote 2004, which was campaigning for the plebiscite, to announce it would disband.
Chairman Sir Martin Jacomb said: "This is the right decision for democracy, the right decision for the UK and it is the right decision for Europe.
"We're obviously delighted that our campaign has been so successful and congratulate the prime minister on his decision."
Mr Cummings, formerly an aide of ex-Tory leader Iain Duncan Smith, said he hoped to raise "millions" from business to fund a campaign
"I don't see any way in which Tony Blair can win this battle," he told BBC News 24.
But he also cast doubt on whether the referendum would actually take place, speculating that Chancellor Gordon Brown would veto such a move.
"I'm still sceptical about it to be honest," he told BBC News Online.
"I think that Blair might promise something but I think that when [Chancellor] Gordon Brown looks at the poll figures, he's going to ask 'what is in this for me?'.
The Tories accuse Blair of opportunism
"Blair's not going to win this referendum and he's going to destroy the Labour government six to nine months after the next election. Is Brown going to let Blair do that?"
Mr Cummings said business opinion was more hostile to the constitution than it was to the single currency - and Mr Blair would be surprised by the strength of feeling.
"What's happening now is that me and some of the key business people involved in the anti-euro campaign are meeting up and chatting about how we should handle this.
"Who are they? People like Rodney Leech, the chairman of Business for Sterling, Michael Spencer, one of the great success stories of the City, and [former Tory treasurer and Dixons supremo] Sir Stanley Kalms."
FOR THE CONSTITUTION
Prime Minister Tony Blair
Most Labour MPs
Most trade unions
A handful of Tory MPs
"It'll be a new organisation, new funding and different people. People who are anti-euro may support the constitution and vice versa ."
"This is fantastic news from my point of view because if Mr Blair does call a referendum I think he's going to get absolutely smashed and then all sorts of other possibilities open up about how you do reform the EU properly."
Meanwhile pro-euro campaign Britain in Europe insisted that the referendum did not alter the fact that "the treaty is good for Britain".
In or out?
Campaign director Lucy Powell said: "We have long been saying that many of those calling for a referendum are motivated not by a love of democracy but by hatred of Europe."
Ms Powell pledged her organisation would campaign strongly for a 'yes' vote.
"Together with our core team in London, our regional campaign network and tens of thousands of supporters across the country will now be making the case for the constitutional treaty with renewed vigour," she said.
AGAINST THE CONSTITUTION
Tory leader Michael Howard
Most Tory MPs
About 40 Labour MPs
UK Independence Party
Business for Sterling group
Simon Buckby, who used to head Britain in Europe, told BBC News 24 that it was important to "seize the moment" and make the case for the constitution.
"We must now decide whether it is right for Britain to be in the European Union playing our leading role at the heart of it or whether the time is now right to get out which is after all the hidden agenda of many of those people who have been campaigning for a referendum on this for a long time."
In the Commons on Tuesday, Tony Blair refused to be drawn on which groups would be officially designated "yes" and "no" campaigns - and therefore entitled to funds from the Electoral Commission.
Liberal Democrat leader Charles Kennedy, who in 1999 shared a platform with Mr Blair, Ken Clarke and Michael Heseltine at the launch of Britain in Europe, urged Mr Blair to throw his full weight behind the "yes" campaign.
In the past, those hostile to Europe had been "allowed to have too much of the running," Mr Kennedy told MPs.
And he called on Mr Blair to "move quickly to re-establish a pro-European British campaign".