Boris Johnson on Tuesday firmly ruled out standing as a Conservative MP at the next general election in 18 months’ time.
The Mayor of London’s comment come after protracted speculation he is plotting a return to Westminster in May 2015, potentially giving him a platform for challenging David Cameron.
But he left open the possibility of seeking a parliamentary comeback after his term as mayor runs out a year later.
Asked at a Westminster lunch if he will be an MP in 2015, Mr Johnson replied: “No, because I have got a huge amount of work to do and I can’t see how I could. I have got to go on and deliver a colossal amount of stuff in London.”
Mr Johnson’s admirers believe a safe Tory seat in the capital or its environs could easily be found for him before the election. They also point out that his predecessor, Ken Livingstone, combined the posts of mayor and London MP for a spell.
Rumours about a possible return were fuelled three months ago when Mr Johnson said he watched MPs debate potential military action in Syria and “for the first time in years I wished I was in Parliament”.
However, he hedged his bets on Tuesday when he was asked whether he wanted to be an MP after he steps down as mayor.
“What happens after two and a half years of being mayor, who knows,” he replied.
“I think most people would agree I have been very lucky to be mayor, and what I have said about it since I got elected, was I thought it was probably the last big job I do in public life and I stick to that.”