Could the next mayor of London be an unknown Tory called Roger, Tony, Gareth or Steve? The outcome of a contest to choose the Conservative candidate for Kensington has thrown up intriguing possibilities about who might run City Hall after November.

Kensington Tories last night chose Boris Johnson’s deputy mayor, Victoria Borwick, as their candidate to replace Sir Malcolm Rifkind. And it could pose a problem for the mayor if he enters a post-election leadership contest to replace David Cameron.

It is highly unlikely - almost inconceivable - Boris Johnson could be both Mayor of London and leader of the Conservative party at the same time. But if he resigns his City hall post more than six months before the next mayoral election in May 2016, he would trigger a costly by-election.

Political observers think Johnson would most likely hang on until November 5th when his resignation would see the official deputy mayor replacing him for the final six months of his term of office. If, however, his deputy, Victoria Borwick, is also a newly-elected MP, similar questions would arise about her ability to do two jobs at once.

If Borwick chose to resign as Deputy Mayor, the post would almost certainly be filled by one of her fellow Tories on the London Assembly - Roger Evans, Tony Arbour, Gareth Bacon or Steven O’Connell. There is, of course, another scenario: David Cameron is re-elected Prime Minister, there is no Tory leadership contest and Boris Johnson MP remains Mayor of London until May 2016.