David Cameron: Britain will pay the price if Sadiq Khan is elected mayor

David Cameron today warned Londoners the whole country would pay the price if they “sleep-walk” into electing Sadiq Khan.

The Prime Minister said a Labour victory would result in Jeremy Corbyn using the capital as a “testing ground” for his policies.

He suggested Mr Khan would hike taxes, hollow out transport investment and damage London’s economy if he won City Hall.

His barrage against Labour’s candidate for mayor is the latest in a series of increasingly bitter attacks as the Conservatives desperately try to hang on to the capital.

It comes after the PM sparked a furious row last week by criticising the Labour frontrunner for sharing a platform with extremists “time and again”.

Mr Cameron today said Londoners would feel the impact of the Labour leader’s hands “on the levers of power” if they voted for Mr Khan.

He told the Standard: “Unless the voters of London act they will feel the consequences of Corbyn’s hands on the levers of power for the first time, using our capital city as a testing ground for his experimental ideas – hiking taxes every London family, gutting transport investment and damaging our economy.

“If London sleepwalks into electing Jeremy Corbyn’s candidate the whole country will pay the price.”

Mr Khan, who the polls put in the lead, nominated Mr Corbyn in the Labour leadership contest - but did not vote for him.

He has been targeted as the party leader’s “man in City Hall” with the PM warning previously that Londoners would be “lab rats” for the left-winger’s policies.

Mr Khan has insisted that he would stand up for Londoners against anybody who threatened their interests, including his own leader.

However, Mr Cameron said his own candidate, Zac Goldsmith, was the only one who would “stand up for them and actually deliver”.