Douglas Carswell is not Ukip's first MP

Conservative MP Douglas Carswell has announced he is defecting to Ukip.

He is, however, not Ukip's first MP, despite what you might have read on Twitter.

That 'honour' goes to Bob Spink, who defected to Ukip in April 2008 after resigning the Conservative whip the month before.

To complicate things further, Spink was redesignated as an independent MP by November 2008; on the grounds Ukip had no whip in the Commons.

Spink has also distanced himself from claims he was a Ukip MP. Speaking in 2009 he insisted he was never a member of Ukip, despite being listed as a Ukip MP when speaking in the Commons up until November 24.

At the 2010 general election he unsuccessfully stood for re-election in Castle Point, Essex, as an independent candidate who backed Ukip.

Carswell's defection, which came at a surprise press conference in Westminster attended by Ukip leader Nigel Farage, included the announcement he was standing down as an MP and planned to fight the by-election triggered in his Clacton constituency, in Essex.

The prominent Eurosceptic said his position as a Tory MP had been made "untenable" and that he did not want to "muddle through" as a Ukip MP until next May's general election, explaining his decision to seek re-election - which he did not have to do.

"It's not enough that I leave the Conservative Party and join Ukip. I will now resign from parliament and stand for Ukip in the by-election that must follow,' he said.