A joke by Mayor of London Boris Johnson about the quality of “sweet” air at Hyde Park Corner has been branded "outrageous" and "inexcusable".

Mr Johnson raised some laughs when he made a quip about London’s “improving” air quality during a speech.

He said: “I'm told now that when we have bad air quality episodes in this country the air in Norfolk is of an inferior quality to the air in London these days.

"The day will not be far off when the people of Norfolk ... the children of Norfolk have to be bussed into London to inhale the sweet air of Hyde Park Corner.”

Air quality campaigners have not seen the funny side to the Mayor’s comments.

Simon Birkett, founder and director of Clean Air in London, has called on Mr Johnson to apologise.

"It's outrageous and inexcusable that the Mayor has joked about bussing children into London to breathe its air.

"Scientists say many roads in central London will tend to have the highest concentrations of nitrogen dioxide, a toxic gas from diesel exhaust, in the world.

"The same scientists have already found that children's lungs can be seriously affected by this sort of traffic pollution in London.

"The Mayor must issue an immediate retraction and apologise to parents and children."

Jenny Bates, air pollution campaigner at Friends of the Earth, said: "It'll be a long time until London's air will even meet the EU limits so Boris might want to hold off on bussing children in from Norfolk for a while yet - the current illegally filthy air is not set to meet targets until sometime after 2030.

"Londoners regularly experience dangerously high air pollution and Oxford Street is the worst pollution spot in Europe for NO2."

What do you think of Boris’s comments – funny or stupid? Add your own comments below.