The resignation of Douglas Carswell as Clacton's Member of Parliament has become official a day after he announced he was defecting from the Conservatives to UKIP.
By parliamentary convention set in 1624, MPs can't actually step down from office. Instead they have to apply for one of two offices of the Crown which are incompatible with being an MP.
So on Friday afternoon a message was released by HM Treasury which made Mr Carswell's resignation official:
"The Chancellor of the Exchequer has this day appointed John Douglas Wilson Carswell to be Steward and Bailiff of the Manor of Northstead."
Douglas Carswell has been a Conservative MP since 2005, first as the MP for Harwich and then, after boundary changes, for Clacton.
He announced on Thursday he was quitting the Conservative Party to seek re-election as a UKIP MP in a by-election.
It's not known when the by-election will be held but it usually takes place within three months of there being a vacancy. The date will be decided in Parliament by the Conservative Party Chief Whip, Michael Gove.
Douglas Carswell has been speaking to ITV Anglia about his historic by-election win in Clacton
Our Political Correspondent Emma Hutchinson on what impact Douglas Carswell's thumping victory in Clacton is likely to have elsewhere.
The country's first Ukip MP has greeted his constituents hours after being elected in a by-election