Media playback is unsupported on your device Media caption Mr Khan and the PM put their earlier differences aside to launch a Remain battle bus - and share a joke about their fathers' very different careers

David Cameron has hailed Labour's Sadiq Khan as "a proud Muslim" and "a proud Brit" as he shared a platform with the London Mayor at an EU Remain rally.

They were launching a Britain Stronger In Europe battle bus and pledge card.

But Vote Leave said the PM's criticisms of Mr Khan during the mayoral contest less than a month ago showed he could not be trusted.

UKIP MP Douglas Carswell said the PM had accused Mr Khan of being a "terrorist sympathiser".

Mr Cameron repeatedly attacked Mr Khan for having a history of sharing platforms with extremists - a claim firmly rejected by Mr Khan - as part of the Conservatives' failed campaign to get Zac Goldsmith elected to City Hall.

At Prime Minister's Questions in the Commons some Labour MPs denounced Mr Cameron as a racist when he questioned Mr Khan's judgment.

At the Remain campaign event in London, Mr Cameron appeared to bury the hatchet.

He shook hands with Mr Khan and congratulated him on his victory in the mayoral contest, telling the crowd: "I'm proud to be here with the mayor of London - with the Labour mayor of London - on this vital, vital issue."

He hailed the fact that "someone who is a proud Muslim, a proud Brit and a proud Londoner can become mayor of the greatest city on Earth. That says something about our country".

The prime minister said he expected many disagreements with the London Mayor but they were both part of "an incredibly broad campaign" in favour of EU membership.

'Cameron flip-flops'

Mr Cameron described himself as a "Eurosceptic" but said the ability to criticise the EU is "a cause of strength in our campaign... we're levelling with people, something the other side refuses to do".

Mr Khan defended his decision to share a platform with the Conservative prime minister - something Labour leader Jeremy Corbyn has refused to do, despite being on the same side as him in the referendum debate.

The London mayor said: "There are many things on which the prime minister and I will disagree. But what's really important is when it's in Londoners' interests for the mayor and the government to work closely together, we will work closely together."

Image copyright EPA

He claimed "more than half a million jobs" in London depended on the UK's membership of the EU, adding: "A vote for Remain means jobs and opportunities."

Staying in the EU meant more measures to fight climate change, "workers' rights protected and more rights for women," he added, and he urged young people to "get involved" in the referendum and register to vote.

Vote Leave spokesman and UKIP MP Douglas Carswell said voters "should not trust David Cameron".

"Just a month ago he attacked Sadiq Khan as a terrorist sympathiser, yet today he hailed him as a great politician as he stood next to him on a shared platform.

"Today he trumpeted the benefits of the European Arrest Warrant but a few years ago he warned that it was dangerous and that it stripped away centuries old rights from the British people.

"David Cameron's flip-flops show that he is not a man of principle - he is just desperate to cling on to power".

Pledge card battle

Mr Cameron and Mr Khan unveiled a "five point guarantee card" listing what they say voters will get if they vote to Remain on 23 June.

The card promises "full access" to the EU single market, protection of workers' rights, "a safer Britain" with co-operation with other EU states, the UK keeping its "special status" within the EU, outside the euro and the Schengen passport-free area and with an opt-out from the EU's aim of "ever-closer union" and "stability".

Media playback is unsupported on your device Media caption Sir Ian Botham: "England should be England"

Vote Leave hit back with a list of five things they say will happen if Britain votes to remain in the EU.

These include much disputed assertion that the UK will continue to "send £350m a week to Brussels," a claim that the free movement of people in the EU will continue "permanently" and that Albania, Macedonia, Montenegro, Serbia and Turkey join, a warning about business red tape, and a claim that "we will continue to be unable to remove criminals and terrorists whose presence in the UK is not conducive to the public good".

In other EU referendum developments: