Next head of BBC must be a Tory says Boris Johnson

Decrying the attitude of a BBC art critic, who told him the new ArcelorMittal Orbit structure at the Olympic Park in Stratford, east London, should be “bigger” and “free”, Mr Johnson said: “There you have everything that is wrong with the BBC and with this country.”

Speaking of his recent election campaign, Mr Johnson says: “I sometimes felt that my chief opponent was the local BBC news – the prevailing view of Beeb newsrooms is, with honourable exceptions, statist, corporatist, defeatist, anti-business, Europhile and, above all, overwhelmingly biased to the Left.”

Mark Thompson, who is due to step down from his role in the autumn after eight years, has admitted the corporation was guilty of bias in the past.

In an interview with the New Statesman in 2010, he said: “In the BBC I joined 30 years ago, there was, in much of current affairs, in terms of people’s personal politics, which were quite vocal, a massive bias to the Left … now it is a completely different generation.”

A BBC spokeswoman said: "BBC News is committed to impartiality and we reject Boris Johnson's assertions of bias.

"Our approach means asking difficult questions of politicians, businesses and unions alike.

"People with trenchant views often find this process uncomfortable but our audience expects us to challenge those in power, as well as those who seek it."

Harriet Harman, shadow culture, media and sport secretary, said Mr Johnson should "keep out of it".

She said: "The importance of the BBC to Britain today is hard to overstate, and it is so trusted because it reports politics impartially. The whole point of the director general of the BBC is that they are neutral."