An 18-year-old man has been arrested on suspicion of murdering Leonne Weeks, 16, who was found dead on a path in Rotherham.
Boris Promises Safer Cycling
Boris Johnson has promised to improve junction safety in the capital following the deaths of six cyclists in a fortnight.
He again stressed that cycling in London is getting safer and that the fatal accidents should not lead to a slackening of cycling activity.
But the Green Party said his junction safety programme does not go far enough.
The mayor's comments came as he addressed a cyclist safety conference in London, an event arranged before last month's accidents.
Mr Johnson said that in the next few months Transport for London will be setting out a programme to make 33 junctions safer.
He said: "There is now a growing chorus of voices who say that the cycling revolution has been going too fast and that we should somehow get all these cyclists off the roads and people look at me in an accusing way.
"This analysis grossly exaggerates my messianic abilities. I am a passionate cyclist, but I am not some kind of Pied Pedaller.
"People go by bike because they love to go by bike.
"We must make cycling even safer and wherever accidents take place, we must respond. We must see what could have been done to prevent them, we must immediately work out what we can do to stop them happening again, and we must address people's fears, well-founded or otherwise."
Mr Johnson said the police's Operation Safeway had, in the past few weeks, led to 755 cyclists being fined for offences such as jumping red lights as well as 1,392 motorists being fined for offences such as talking on their mobiles or jumping lights.
He went on: "We will continue to expand and improve the superhighways and yes, where it is possible and sensible, we will segregate those routes, as we have done at Stratford.
"The cycling revolution will continue, and it will accelerate. This is not the time to slacken off or give up because if we get this right, the prize is huge. London should be in many ways a perfect city to ride a bike.
"If we can get Londoners on to bikes, we can take the pressure off public transport, we can reduce traffic and I believe we can help people to be fitter, calmer, less hassled and to enjoy the glories of the city in a way that is different every day."
London Assembly Green Party member Darren Johnson said: "Over two years ago, the mayor promised to urgently overhaul 500 of the capital's most treacherous junctions but what we are now seeing is the mayor's ambition shrinking as cycle casualties are rising."
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