Ukip offered not to fight the Tories at the next general election in return for a pledge to hold a referendum on the Lisbon Treaty even after it was ratified, the eurosceptic party's new leader revealed today.
Ex-Tory peer Lord Pearson of Rannoch told the Times that he took the proposed deal to the Conservative leader in the upper house, Lord Strathclyde, after Ukip beat Labour into third place in this June's European elections.
Last month Mr Cameron dropped his promise of a national vote when the treaty was finally ratified by all EU member states - angering the new Ukip leader as well as many of his own backbenchers.
Lord Pearson, who was elected by party members this afternoon, was acting on behalf of predecessor Nigel Farage who has stepped down to concentrate on his own general election campaign to oust Commons Speaker John Bercow and his role as an MEP.
The peer told The Times that he had offered to "disband" the party - but a spokesman insisted that in fact the deal had only ever involved calling off its general election campaign.
"We made that offer but we didn't get an answer," he said.. "I'm so angry with them now."
Shadow Europe minister Mark Francois said: "We don't make policy on the basis of secret deals with other parties; we decide our policies on the basis of what is right for the country.
"As we have said, a made-up referendum after ratification would be pointless."
Lord Pearson earlier polled 48% in a leadership ballot of party members of Ukip, which campaigns for Britain's withdrawal from the European Union.
He was granted a peerage by Margaret Thatcher in 1990 but had the Tory whip withdrawn in 2004 after suggesting voters should support Ukip in that year's elections.
In his acceptance speech he said his ambition was to win enough support to force a hung Parliament in next year's general election.
"If you want to go on being deceived by the main parties, then stay in them and vote for them. If you don't, the only way forward now is Ukip. It is the only show in town," he said.
He said the Lisbon Treaty was the "last nail in the coffin" of Britain's democracy.
The peer admitted he was "not much of a politician" but said that he might be appealing to voters disillusioned with the present system.
He made the comments after being challenged by Channel 4 News over a previous claim he made that UK Muslims breed 10 times faster than other people.
"I got that wrong. I'm not, I'm afraid, much of a politician," he said, putting the error down to jet lag.
Asked if that was a handicap for a party leader, he said: "We shall see. I think the British people have had enough of professional politicians; that's one reason I think we've been elected."
Lord Pearson told The Times: "After we came second in the European elections in May, David [Lord] Willoughby de Broke and I went to see the Tory leader in the House of Lords, Tom Strathclyde.
"We said: 'Look, we have done quite well, better than we thought, if you guarantee us a referendum on 'in or out' and you give a genuinely free vote to the Conservative Party, we will disband'.
"A referendum on a ratified Lisbon treaty would have become about 'in or out', which is why the political class wouldn't do it."
He later made clear that the result could have been the overall disbandment of the party if the result of the referendum had been to achieve the aim of British withdrawal.
"When we had the referendum, which we believed we would win, we would then be out of the European Union and at that point, it would have been up to Ukip but it probably would have disbanded," he told BBC Radio 4's Today programme.Reuse content