Tory MP Douglas Carswell has defected to the UK Independence Party and will stand down as MP for Clacton to seek re-election in a by-election.

If he wins the by-election he will be the first UKIP MP to take a seat in Westminster.

The maverick Eurosceptic backbencher said he wants to "shake up" the cosy Westminster "clique".

He unveiled his surprise announcement at a news conference in central London.

He told reporters he did not believe Conservative leader and Prime Minister David Cameron was "serious about the change we need".

He said the decision to jump ship from the Conservatives had given him "sleepless nights" but he wanted to see "fundamental change in British politics" and UKIP - a party he believed belonged to its members rather than a "little clique" of political insiders - could deliver it.

UKIP leader Nigel Farage, who this week was selected to fight South Thanet at the 2015 general election, said it was the "bravest and most honourable" decision he had ever seen in British politics.

Clacton isn't going to be narrow at all. UKIP are getting at least 50%.

Apparently Matthew Parris's column in The Times the other week (paywall; also likely to bring Danny out in hives from sheer metropolitan liberal elitedom) is being used actively by Ukip in their campaigning against the Conservatives - a few councillors defected along with Carswell the day he announced it, but there have actually been more defections since the Parris column and it's been pretty disastrous for the Tories locally.

To begin with it was polled that Ukip were between 55-65% of the vote and the Tories were on about 20% (and interestingly only went up to 27% when people were asked how they'd vote if Boris ran) with Labour behind on around 15%. There haven't been any polls since the Parris column but it would be absolutely delicious if Labour overtook the Tories come May 9th.

Conservative MP Mark Reckless has announced that he is leaving the party to join UKIP.

The Rochester and Strood MP made the announcement at the UKIP party conference, in Doncaster.

Delegates started to spontaneously chant "UKIP, UKIP" when Mr Reckless announced his decision, which he said was not easy.

The move comes just weeks after Clacton MP Douglas Carswell defected from the Conservatives to join UKIP.

Mr Carswell announced that he would stand down as an MP in his constituency to seek re-election in a by-election.

Commenting on his decision, Mr Reckless said he had not taken it lightly.

He claimed the Conservative leadership was "part of the problem that is holding our country back".

Appearing on stage to a rapturous reception at the conference, Mr Reckless said voters felt "ripped off and lied to".

He won his seat in 2010 with 23,604 votes - 49% of the vote. Labour's Teresa Murray came second, with 13,651 votes.

So a second Tory MP decides to waste public funds by calling an unnecessary by-election. Whoever wins will be an MP for just five months before parliament is dissolved for the General Election.

Would you have kicked up this kind of fuss had the Alliance done the same in 1982 as a matter of course?

I'm starting to think UKIP could do even better than anyone thought. Up to 20% share of the vote at next year's election perhaps.

Thank god we have a FPTP voting system which is heavily biased against parties like UKIP. Plus it looks like it'll fracture the Tory vote!