Former Tory MP Mark Reckless has admitted he could lose his seat after defecting to UKIP and calling a by-election

Rebel MP Mark Reckless has admitted that he could lose his seat and become 'a footnote in history' after triggering a by-election by joining UKIP.

The ex-Rochester and Strood Tory MP admitted his switch, announced on the eve of the final Tory party conference before the 2015 general election, came with 'enormous personal risk'.

But he said he could not keep his election promises to slash immigration and cut Britain's mounting debt pile as a Tory MP.

Mr Reckless announced that he was leaving the Tories to join UKIP after being introduced by Nigel Farage at the party's conference in Doncaster on Saturday.

He has faced an onslaught of criticism from his former Conservative party colleagues since his defection, with some openly accusing him of lying about his plans to defect.

Andrew Mackness, chairman of the Rochester and Strood Conservatives, said Mr Reckless had agreed to join a Tory campaign bus the day before he quit.

But in an interview with BBC Radio Kent, Mr Reckless said that had the Tories found out about his plans in advance, he would have been attacked in 'the most vicious, vicious way'.

He said: 'You cannot announce these things in advance and what the Conservatives would have liked me to have done is to have told them so that they could have launched a media onslaught on me ... rather than me explaining the positive reason of why I wanted to join Ukip and why I wanted to keep the promises of my constituents.'

He added: 'I'm running an enormous personal risk. I may be a footnote in history. I may be wrong. Perhaps the people of Rochester and Strood don't feel as I do.

'Perhaps they don't feel let down. Perhaps they are not worried about the Government breaking its promises.

'It's a big risk. I think I have a fighting chance but I may lose. I will take my case to the electorate here and the people I have worked for and done as much as I possibly could over the last four and a half years.

'I will ask them. They will make the decision.'

The defection has caused fury in Downing Street – with the Prime Minister vowing to do everything he could to win back the seat for the Tories.

Mr Reckless won the seat for the Tories in 2010 with a 10,000 majority ahead of Labour. But UKIP did not put up a candidate.

In an impassioned address to party activists, the Prime Minister said Mr Reckless had lied to his former party 'over and over and over again' about his loyalty.

The PM also warned any backbenchers against following Mr Reckless and Mr Carswell.

He said: 'I would say one other thing to those people – you have got elected with the help of Conservatives, who stuffed envelopes, who walked streets, who knocked on doors, who worked their guts out to get you to be a member of parliament, you have let those people down.

'We are coming for you in by-elections and we are going to throw everything we can at you.'

London Mayor Boris Johnson, who will address a rally at the Tory conference today, issued an appeal to any further would-be Tory defectors, urging them not to break ranks and join Nigel Farage's 'people's army'.

The Prime Minister, listening to William Hague's final party conference address in Birmingham yesterday, has vowed to throw everything at Rochester and Strood to hold the seat

Writing in his weekly column in the Daily Telegraph, Mr Johnson said Conservative MPs would be 'utterly nuts' to desert the party for Ukip as they simply risked handing power to Labour at next general election.

But former environment secretary Owen Paterson, who was removed in the last Cabinet reshuffle, called on the Prime Minister to reach out 'respectfully' to disaffected Conservatives who might be considering voting for Ukip.

He told the BBC Radio 4 Today programme: 'We have to be absolutely clear to those small C conservatives out there who may be sitting back at the moment - some might go to protest parties like Ukip.

'We have got to be respectful of them and we have got to make a very clear, intelligent case that the only national organisation that can resolve the long-term problems of the UK is the Conservative Party.