London Mayor Sadiq Khan has fired the starting gun on local election campaigning in the capital, attacking the Conservatives at council and national level.

Mr Khan said Tory politicians had failed voters on housing, health and polluted air, as he revealed Labour would make Tory boroughs Wandsworth and Barnet top targets.

The Tories hit back accusing Mr Khan of a string of broken promises, but the party’s own polling information points to a difficult round of elections in the capital in May.

Mr Khan released an analysis which he said proved Tory policy at national and local level was hitting Londoners.

The Mayor said official data showed Labour councils in London have on average built almost 70 per cent more affordable housing than Tory councils since 2013.

He added that 25 per cent of all housing built by the average Labour-run council since 2013 has been affordable compared to 17 per cent from Conservative boroughs.

Mr Khan said: “For too long, Londoners have suffered Tory cuts to their most vital services – from the NHS, to social care, to youth centres.

“Tory-led councils have done nothing to build the genuinely affordable homes Londoners need, and in many cases the Tories have actively tried to block efforts to clean up our filthy air.

“It is time to turn these councils red, so Labour can govern for the many, not the few.”

Turning to the NHS he said that last month every single A&E ward in London missed its waiting time target for 95 per cent of patients to be seen within four hours.

London’s hospitals had only met their cancer targets to treat 85 per cent of patients within 62 days of an urgent referral, in two months out of the last two years.

He hit out at Tories on the London Assembly for voting against his measures to introduce a new ultra-low emissions zone, and T-charge to get the dirtiest vehicles off the road.

Responding, Paul Scully MP, Conservative Vice Chairman for London, said: “Since the Labour Mayor of London was elected less than two years ago, all Londoners have had to stomach is broken promise after broken promise.

London housing is set to be top of the campaign agenda in May (Getty)

“In key areas such as improving transport, preventing crime and delivering value for money on council tax, Labour are quick to ditch their election promises and let Londoners down time and time again.

“It’s the Conservatives who are working hard locally to keep council tax low, our streets secure and to deliver the services we all rely on.”

They accused the mayor of having broken promises over stopping transport strikes, freezing fares and also building homes – pointing to data in August showing that no social housing had been built in the last 12 months.

Elections analyst and Conservative peer Lord Hayward said in January that the Tories face likely defeat in two London councils and the “fight of their lives” to cling on to three others which were previously seen as safe.

The Conservatives look certain to be beaten in Kingston by the Liberal Democrats, according to his analysis.