The Mayor of London’s comments are the first time that he has directly said whether or not he will be wants to be an MP in 2015 and are likely to bring an end to months of ‘will he, won’t he’ speculation about a return for Mr Johnson to Parliament at the 2015 general election.

Asked at a lunch of the Parliamentary Press Gallery if he will be an MP in 2015, Mr Johnson said: “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.”

However Mr Johnson, who was MP for Henley between 2001 and 2008, was more equivocal when it came to whether he would like to be an MP after he stands down as expected as Mayor in 2016.

He said: “What happens after two and a half years of being mayor, something will crop up, I have always wanted to have a career in romantic fiction, or something like that.

“I think most people would agree that I have been very lucky to be mayor, and what I have said about it since I got elected, was that I thought it was probably the last big job I do in public life and I stick to that, so there you go.”

Mr Johnson first said that he would like to be mayor again in the summer, after he watched MPs debate whether Britain would intervene militarily in Syria.

In an interview with the Financial Times’ Magazine, Mr Johnson said: “During the whole Syria thing, for the first time in years, I wished I was in Parliament. I watched that and I thought … I wished, I wished.”