Boris attacks top Tory's claim that crime in London is like The Wire

Boris Johnson has lashed out at shadow home secretary Chris Grayling for claiming that parts of Britain suffer from crime similar to that portrayed on US TV series The Wire.

The Mayor said that it was "absolute nonsense" to compare the capital to Baltimore, the American city where the television show is set.

Mr Johnson's attack on his senior Tory colleague is yet another challenge to the Conservative party nationally, coming less than a month after he infuriated David Cameron by demanding a referendum on Europe. Mr Grayling claimed in the summer that parts of the UK now resembled Baltimore's drug and gun culture. "Far too many of those features of what we have always seen as a US phenomenon are now to be found on the streets of Britain as well," he said at the time.

Last month, figures showed the number of gun crimes in London had nearly doubled in the past six months.

But the Mayor used a public meeting last night to declare that the figures were largely down to youths pretending they had a weapon. He said the number of killings was well down. "Someone the other day compared London with Baltimore, absolute nonsense. You know, this programme, The Wire in Baltimore," he said.

"There are 35 murders per 100,000 in Baltimore, there are approximately three murders per 100,000 in London. It is far, far more dangerous in Baltimore than it is in London, especially for gun crime."

Mr Johnson also described the failure of teachers to maintain discipline in schools as "terrifying".