Union-basher Boris Johnson said yesterday he will seek a safe seat before next year’s general election as campaigners warned his prime ministerial ambitions could unleash a massive assault on workers’ rights nationwide.

The buffoonish London Mayor insisted he would also serve out his term at City Hall and keep his existing rent-a-gob role with the Daily Telegraph meaning he could be part-timing three highly paid jobs by this time next year.

At a Q&A session after a speech on the European Union, Mr Johnson said it had become “pretty clear that I can’t endlessly go on dodging these questions as I’ve tried to do.

“So, let me put it this way,” he said. “I have not got any particular seat lined up but I do think in all probability — since you can’t do these things furtively, I might as well be absolutely clear — in all probability I will try to find somewhere to stand in 2015.”

But North London left Labour MP Jeremy Corbyn warned last night that falling for Mr Johnson’s comedy image could be dangerous.

He told the Star: “Beneath this Billy Bunter, Bertie Wooster image that Boris Johnson has so carefully cultivated for the past 20 years lies a Tory politician who has refused to meet unions and who has been driving through anti-union programmes during his time as mayor.

“Now he evidently wants to take over from Cameron and do the same to the rest of the country. Be warned!”

One union that Mr Johnson has refused to meet is Tube union RMT. 

The union’s acting general secretary Mick Cash blasted the mayor for his record of broken promises. He said: “The same Boris Johnson who told us he wouldn’t close tube ticket offices also told us he would complete his full term as mayor without a return to Parliament, a pack of lies on both counts.

“London now looks like being lumbered with a lame duck Mayor until 2016 while Boris jumps ship to fulfil his personal political ambitions.

“It is a shocking and sordid way to treat the people of London and will add fuel to RMT demands for a halt to job and service cuts on the Tube.”

Former London mayor Ken Livingstone said Labour must “pin down” Mr Johnson on his hypocrisy.

Asked if he wished his successor well, Mr Livingstone added: “I wish him well in life, I’d just prefer him to be going into a monastery where he won’t be doing the rest of us any harm.”