Boris Johnson has now resigned his seat as Member of Parliament for Henley on Thames, not through the mechanism of the Chlitern Hundreds, but through that of the Manor of Northstead ("The position of Crown Steward and Bailiff of the Manor of Northstead is now used as a procedural device to effect resignation from the House of Commons, since British MPs are not permitted simply to resign their seat. Under the Act of Settlement, any Member of Parliament accepting an office of profit under the Crown must give up his or her seat.")
HM Treasury Press Release:
04 June 2008
Manor of Northstead
The Chancellor of the Exchequer has today appointed Alexander Boris de Pfeffel Johnson to be Steward and Bailiff of the Manor of Northstead.
So, bearing in mind possible party political considerations regarding the timing of the by-election, Boris Johnson has resigned his seat as an MP one month after being elected Mayor of London.
This contrasts very favourably with Ken Livingstone, who clung on to his seat as MP for Brent East, "double dipping" from the public purse for over a year after being elected as Mayor of London for the first time ion 4th May 2000. He only left when Parliament was dissolved on 14th May 2001, in preparation for the June 2001 General Election.