Mr Steele was hired to find information on Mr Trump by a Washington-based consultancy that was being paid by Republican opponents of the president-elect – the BBC claimed they were acting on behalf of fellow nominee Jeb Bush – and, later, by Democrats.

However, he decided the information was so sensitive that it should also be passed on to the FBI and to his old colleagues at MI6.

The Daily Telegraph was told during a meeting with a highly-placed source in Washington DC last October that the FBI had contacted Mr Steele asking if they could discuss his findings with him. The source said that Mr Steele spoke to officials in London to ask for permission to speak to the FBI, which was duly granted, and that Downing Street was informed.