Johnson's great voice for television

The Oxford-educated Old Etonian says he was sacked from presenting BBC Radio 4's The Week in Westminster because the station thought him "too posh".

The Daily Telegraph columnist and newly-appointed editor of The Spectator magazine believes he has been the victim of what he calls "vocal correctness".

An official BBC statement said Mr Johnson had been removed from the rota of presenters because the show had been given a new Saturday morning slot.

"It's a question of tone, not accent," said Radio 4's Marion Greenwood. "Presenters with what you might describe as plummy accents abound on the network."

The station seems keen that the political programme should complement its new Saturday neighbours.

Greenwood said Radio 4 was taking care to include nothing "that will jar, that doesn't seem appropriate for a Saturday morning".

Veteran DJ John Peel found success with a Liverpudlian accent

It seems unlikely the decision to end Johnson's tenure on the show has anything to do with his self-confessed Conservative-style thinking.

"It's not that right-wing opinions are not wanted," Radio 4 is quick to point out. Indeed journalists from across the political spectrum continue to contribute to the programme.

Could Boris be the first casualty in a war against those "what speak proper" - the victim of a fresh assault on the mode of speech once dubbed BBC English?

Professor John Wells, an expert on phonetics from University College London, thinks the battle over pronounciation has been more gradual.

He said the last century had seen a "reduction of the deference afforded to people who talk like Boris".

"People are no longer automatically inclined to assume what people from the upper classes do is worthy of imitating," he said.

With speakers of received pronounciation no longer monopolising higher education, the media and the government, the accent may have become as much a liability as any other.

"People have prejudices about the social group who use a certain accent, rather than the accent itself," said Professor Wells.

"For different purposes different accents are a way to get on."

Radio veteran John Peel, whose show Home Truths will precede the Borisless Week in Westminster, swapped his public school accent for a Liverpudlian drawl during Beatlemania.

Gregory de Polnay speaks to BBC News Online

Gregory de Polnay, head of voice at the London Academy of Music and Dramatic Art, thinks Johnson could also reinvent his speech.

He said the journalist's voice was that of someone "used to commanding, used to being heard".

Standardising Johnson's vowel sounds would be the first hurdle.

"All those rather clipped vowel sounds that go with that accent we could iron out," said Polnay.

Johnson's "nasality" would also have to be addressed, ensuring he does not push the sound of his voice down through the nose.

"Somewhere along the line somebody has said that [nasal] sound can appear to be more authoritative," he said.

If he can also defeat the temptation to exaggerate his diction by pushing out phrases, Polnay thinks Boris could soon master a radio-friendly "neutral" accent.