Boris Johnson has formally announced he is standing down as MP of Henley, triggering a by-election in the staunchly Conservative constituency.
The result is not a surprise to anyone in Westminster. David Cameron has already revealed his candidate for the area - local man John Howell.
Mr Johnson gave up his constituency work due to the burden of his mayoral work.
"This job here is simply too big and it's growing all the time," he said at his first City Hall press conference as London mayor.
Asked about advice for his successor, he said a willingness to listen and patience were crucial when dealing with his consitutents - the "nicest, kindest and some of the most eccentric people in Britain".
"The most important. [characteristic] is that they are Conservative," he added.
Mr Howell said he considered it a "huge privilege" to be selected for his home constituency.
"I plan to spend the next few weeks talking to as many local people as possible about the issues that affect us all in South Oxfordshire," he said after his selection meeting.
"I hope that when the by-election eventually comes, the people of this area will give me the opportunity to serve as a committed and effective local MP."
Speculation has been growing since the Crewe and Nantwich by-election that Tory strategists may seek to maintain the party's momentum by calling another by-election.
Henley is a traditional Conservative seat; Mr Johnson's 12,793 majority in the 2005 election gave his party 54 per cent of the vote. His nearest challenger was the Liberal Democrats who won 12,101 votes.
The Labour candidate for Henley is Richard McKenzie while the Lib Dems' is Stephen Kearney.