Speculation is mounting that more Conservatives could leave the party to join Ukip following Tory MP Douglas Carswell's sensational defection yesterday.
Carswell was just one of nine Tories who were "wined and dined" by millionaire Ukip donor Stuart Wheeler at a series of "discreet" lunches in Mayfair, it was reported Friday.
Sparking further speculation about further defections from the Tory ranks, a source told the Daily Mail that the MPs involved "held intensive talks with Ukip about defecting."
UKIP leader Nigel Farage (left) with Douglas Carswell
"Stuart is quietly confident that more may follow Douglas," the source apparently said.
Ukip leader Nigel Farage has meanwhile already predicted further defections should Carswell win a by-election and become the Eurosceptic party's first MP.
The Tory deserter will return to his Clacton constituency today flanked by the Ukip leader, as the pair plan a completely unexpected by-election campaign following the shock announcement yesterday.
Carswell quit the Commons to re-stand under the Ukip banner. Writing in the Independent today Farage claimed there were other MPs among both Labour and Conservative rank-and-file who could follow suit.
He said: "There are an increasing number of Conservative and Labour backbenchers who not only support Ukip fully in what it is trying to achieve but view the impact of open-door immigration and its effects on the lives of ordinary people with increasing urgency.
"So if Douglas Carswell wins this by-election and those backbench MPs with a favourable view of Ukip believe they are more likely to win their seats as Ukip than as Tory or Labour, then more will follow.
He said the Clacton by-election is of "huge significance not just to the future of Ukip but to the whole of British politics."
"It will indeed be our high noon."
Rounding up the speculation, HuffPost UK presents six Tories who could one day be tempted to follow Carswell to Ukip.
Announcing his defection from the Tories, Carswell said he did not believe David Cameron's EU referendum policy was "sincere", saying the leadership wanted to secure "just enough" to pretend change was happening.
Cameron condemned the move as "deeply regrettable" and now faces a tricky party conference season overshadowed by the campaign.
In his announcement, Carswell said: "No one cheered David Cameron's Bloomberg speech more loudly than me ... but there's been nothing since. They haven't thought it through.
"There is a world of change and opportunity out there ... ministers are simply not up to giving us the kind of realignment we need."
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Carswell said it would have been easier for him to "muddle along" as a Tory backbencher until next May, but he wanted to do the "honourable" thing.
The Prime Minister led dismay at the announcement, which caught all sides by surprise at a press conference called by Farage.
Cameron said: "It is obviously deeply regrettable when these things happen and people behave in this way. But it is also, in my view, counter-productive.
"If you want a referendum on Britain's future in the EU, whether we should stay or go, the only way to to get that is to have a Conservative government after the next election.
"That is what until very recently Douglas Carswell himself was saying."
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Speaking to the BBC Newsnight programme Work and Pensions Secretary Iain Duncan Smith, who lead Tory revolts over Europe and the Maastricht Treaty in the 1990s, said Carswell "Has made a big mistake."
"I know Douglas quite well really and he is that classic kind of figure who has never really sought or wanted front bench appointment, but really agitates from the backbenches. It's an historic position to be in. I regret he's gone."
"This is very much a Douglas Carswell moment - in other words he is very much an individual who would make this kind of decision ... we were all surprised but at the same time not that surprised in a funny sort of way."
The date for the by-election is yet to be set but is likely to be held within weeks. Parliamentary rules require an election between 21 and 27 days after a writ is moved to fill the vacancy.
Reports have suggested a mid-October date for the poll - with October 9 the last available Thursday if the writ is moved on September 12, the final day of the two week September sitting.
Carswell's defection has also led to renewed calls by some Tory backbenchers for the party to form a pact with Nigel Farage's party at the 2015 general election.
Conservative MP Jacob Rees-Mogg told The Huffington Post UK yesterday: "I think the Tories and Ukip should work together because we have pretty similar aims, whereas by being divided, we split 'small-c' conservatism and make it all the more likely that Ed Miliband will win."
But asked if he might follow Carswell's lead by defecting to Ukip, the North-East Somerset MP said: "I certainly wouldn't".