The British spy behind a notorious 'dirty dossier' on Donald Trump's links to Russia is being sued by three oligarchs in the High Court.

Former MI6 man Christopher Steele's report on the newly elected US President in 2017 alleged he was in Vladimir Putin's pocket and claimed he threw an orgy with prostitutes on a Moscow trip.

Mr Trump called it 'fake news' and blasted Mr Steele as a 'failed spy'. Now the 55-year-old is being sued in London by three Russians named in the file and has been asked to back up the accuracy of his dossier.

They want him to pay damages and tell the world his report was inaccurate.

The trio - banker Peter Aven, billionaire financier Mikhail Fridman and oil tycoon German Khan - deny his claims that they did Putin's bidding.

Before a hearing last month, father of three Mr Steele suggested he would barely answer any questions, claiming it would identify his sources.

He argued his dossier was reporting what he was told and was not definitive truth.

Christopher Steele (pictured, who wrote a notorious 'dirty dossier' on Donald Trump's alleged links to Russia, is being sued by three oligarchs in the High Court

President Trump called Steele's report 'fake news' and branded the MI6 veteran a 'failed spy' (pictured meeting with Vladimir Putin during a press briefing in July 2018)

But the judge, Mr Justice Warby, warned he expected Mr Steele to give answers and failure to do so could count against him.

The dossier was unveiled in January 2017 as Mr Trump prepared to enter the White House and was commissioned by a Washington consultancy. The contract to investigate Mr Trump's links to Russia was handed to Orbis Business Intelligence Ltd - co-founded by Mr Steele, a Russian expert for MI6 for 22 years.

Six months later, it was leaked to US Democrat politicians and the media, containing claims Mr Putin spent years compiling an embarrassing 'kompromat' file on the President.

Mr Steele said Russian spies claimed they filmed an orgy Mr Trump staged in a hotel room there on a business trip.

And the dossier said that not only had Mr Putin's men given Mr Trump information useful in his election campaign in 2016, but that his allies had in return handed over information on Russians in America.

Steele is being sued in London by three Russians including German Khan (left) and Mikhail Fridman (right) named in the file and has been asked to back up the accuracy of his dossier

Peter Aven (left) and Mikhail Fridman (right) deny Steele's claims that they did Putin's bidding

Mr Aven - who has owned a home in Wentworth, Surrey - Mr Fridman, and Mr Khan are disputing some of its veracity. They claim references to them are inaccurate and damaging.

The case has been held up because the claimants argue Mr Steele should be forced to answer questions and prove his claims are true, or pay up.

The ex-spy's lawyers said some allegations were already in the public domain. And Mr Steele insisted he would not discuss his sources, claiming it could endanger them.

Mr Justice Warby said: 'I may be called on to rule whether he should be compelled to answer a question.' And the judge warned he was not convinced Mr Steele would be able to insist his dossier accurately reported what he had heard - suggesting he would have to prove it was not inaccurate.