The Conservatives were bracing themselves for further defections to Ukip as voters went to the polls in the Rochester and Strood by-election today.

Conservative jitters about Ukip winning its second elected MP increased after Mark Reckless, the former Tory MP who defected to Ukip and triggered the by-election, claimed that two other Tory MPs were considering switching to Nigel Farage’s party.

The Tories already fear defeat in today’s contest, after a series of opinion polls during the campaign gave Ukip a comfortable lead despite five visits by David Cameron and Tory promises to “throw the kitchen sink” at what is seen as the most important by-election for many years.

Now Mr Cameron faces the prospect that the bloody nose he expects when the result is announced in the early hours of tomorrow morning will not be the end of his Ukip nightmare. Loyalist Tory MPs fear further defections will give Mr Farage momentum until next May’s general election.

Who's next? Conservative MPs who could defect to Ukip Show all 8 1 /8 Who's next? Conservative MPs who could defect to Ukip Who's next? Conservative MPs who could defect to Ukip Chris Kelly Won Dudley South with majority of 3,856 in 2010 but is standing down next May. Has been wooed by Ukip, which is targeting his seat, but insists he will not join Nigel Farage’s party. Has declined to say why he is leaving Parliament Facebook Who's next? Conservative MPs who could defect to Ukip Mark Pritchard Former secretary of the influential Tory 1992 Committee. MP for The Wrekin. Majority 9,450. Photographed with Nigel Farage at an event recently but said it was just a “friendly photo" Who's next? Conservative MPs who could defect to Ukip Philip Hollobone MP for Kettering. Majority 9, 904. He said in 2013: “So many constituencies are now marginal because Ukip is now providing a fourth dynamic into what has previously been a three-party dynamic. I think we could end up with a situation where in selected seats, where the Conservative candidate or member of Parliament is in favour of leaving the EU, they would endorse him in those seats" Rex Who's next? Conservative MPs who could defect to Ukip David Nuttall MP for Bury North. Majority 2,243. Outspoken right-winger. Has said it would be “beneficial” if the Tories and Ukip could agree a “common programme” in order to unite the right in British politics Twitter Who's next? Conservative MPs who could defect to Ukip Nadine Dorries MP for Mid Bedfordshire. Majority 15,152. Lost Tory whip after appearing on ITV’s “I’m a Celebrity…Get Me Out of Here,” but later reinstated. Has said her constituents some constituents feel a "huge amount of empathy with Ukip". Hinted at standing on a joint ticket but denied she will defect PA Who's next? Conservative MPs who could defect to Ukip Jacob Rees-Mogg MP for Somerset North East. Majority 4,914. Independent-minded like Douglas Carswell. Has called for an electoral pact between Tories and Ukip. “There are many members of Ukip who are very close to the Conservative Party and there are many Conservatives to whom Ukip looks favourably,” he said in May David Hedges Who's next? Conservative MPs who could defect to Ukip Gordon Henderson MP for Sittingbourne and Sheppey. Majority 12,383. Wants Britain to leave the EU and admits he has been “sounded out” by Ukip. But insists the party has “no principles,” saying: “I’d sooner lose than be a turncoat” Who's next? Conservative MPs who could defect to Ukip Peter Bone MP for Wellingborough. Majority 11,787. Independent-minded backbencher who hates the Coalition. Has said: “Somehow the Conservatives and Ukip have got to work together and have some sort of [electoral] pact or accord” UPPA/Photoshot

Mr Reckless said: “During the campaign I have spoken with two Conservative MPs about the possibility of their moving over and I think they will want to see what the [by-election] result is before making any decisions. One of them I had discussions with by telephone and the other I met in an undisclosed location, not in the constituency. It is a very individual decision. And I feed back to Nigel [Farage] on those conversations.”

Although Tory ministers played down the possibility of more MPs jumping ship, party whips are powerless to stop that since switchers are unlikely to advertise their intentions in advance. Mr Reckless consistently denied planning to join Ukip before appearing at its annual conference in September to announce his decision.

Speculation is rife at Westminster about likely Tory defectors. Peter Bone, MP for Wellingborough, will speak at Cambridge University tonight in favour of a motion saying that “Ukip has been good for British politics.” He said: “My view is that Ukip membership should come back and be part of a centre-right party in this country.”

John Baron, MP for Basildon and Billericay, is also tripped as a possible switcher after Ukip dropped its candidate in a neighbouring seat to “keep it warm” for him. But Mr Baron said today: “Rest assured I'm happy where I am. That is standing for the Conservatives in Basildon and Billericay - as long as they still want me to!”

Mark Pritchard, MP for The Wrekin, sparked more rumours after being photographed with Mr Farage at an event, but said later it was a “friendly photo, not a sign of any political allegiance.”