David Cameron has ordered his diplomats in Washington to reach out to Donald Trump to repair relations in case the Republican front runner pulls off an improbable White House win.

The Prime Minister slammed Mr Trump at 'divisive, stupid and wrong' last year in the wake of controversial remarks about stopping Muslims entering America.

Responding to a petition calling for Mr Trump to be banned from visiting Britain, Mr Cameron said he opposed an outright ban but told MPs: 'If he came to visit our country I think he would unite us all against him.'

There are fears in Government the remarks could leave the 'special relationship' between Britain and America on ice were Mr Trump to enter the White House in January.

Donald Trump, the Republican front runner, is set to be contacted by British diplomats as No 10 worries about mending relations after David Cameron launched a fierce attack on him last year

Sir Kim Darroch, Britain's ambassador to America, has been told by No 10 to prioritise building links with the foreign policy advisers in Mr Trump's team.

A Government source told The Times: 'I think it’s fair to say that the prime minister wouldn’t say that the whole of the UK would unite against Donald Trump if he was asked now.'

Downing Street today insisted the meetings were a normal diplomatic move ahead of major elections.

Mr Cameron's official spokeswoman said: 'It's a well known job of our ambassadors and embassies to know the political leading figures wherever they are in the world and to engage with them.

'Obviously as we get close to the point where nominees for the US Presidency are decided it makes sense to ensure we have got good links to those candidates.'

Asked if Mr Cameron still believed Mr Trump was 'divisive, stupid and wrong', the spokeswoman added: 'You've got (the Prime Minister's) words.'

Mr Trump sparked international outrage in the wake of the Paris attacks when he said: 'We have places in London and other places that are so radicalised that the police are afraid for their own lives.

'We have to be very smart and very vigilant.'

London Mayor Boris Johnson - who could be in No 10 by the time of a Trump victory if Britain backs Brexit in June - led criticism of the statement.

But Mr Trump stood by his claims last month, telling ITV: '(Boris) said like they have no problems in London at all.

David Cameron could have to welcome Donald Trump to Downing Street within months

'But I was written letters and phone calls talking about London and talking about the fact that I was right.'

The Republican front runner named a new team of foreign policy advisers last month, including London-based lawyer George Papadopoulos.

Mr Trump's White House run appeared to be back on track this week after the tycoon secured a big win in his home state of New York.

The results mean Mr Trump continues to hold a significant lead over his nearest rival, Ted Cruz, in the race for the Republican nomination.

Last night, Mr Trump called on his two rivals to clear out of the Republican presidential race Thursday night, saying he's the only GOP White House hopeful who can possibly win the support of a majority of Republican National Convention delegates.

'Honestly, Cruz and Kasich have no path to victory,' he said in Harrisburg, Pennsylvania five days before the Keystone State's primary election. 'It's over. It's over.'

Trump, Texas Sen. Ted Cruz and Ohio Gov. John Kasich are the last survivors of a field that began with 17 contenders.

Cruz is running in second place on the strength of what Trump called a 'crooked' delegate allocation process, but the real estate tycoon insisted he's 'kicking a**' anyway.

If Mr Trump does win the nod at July's Republican National Convention, recent tradition might suggest a visit to Britain ahead of November's general election.