Portsmouth-schooled Brexit Party worker, 19, says he was behind leak story that led to US ambassador Sir Kim Darroch's resignation

Steven Edginton’s identity has been revealed in the Mail on Sunday, 11 days after Sir Kim Darroch stepped down from his post following a spat with US president Donald Trump.

In leaked cables it was reported Sir Kim wrote a letter in which he branded Mr Trump’s White House 'inept' and 'utterly dysfunctional'.

The president hit back on Twitter after the story took off, calling the ambassador a ‘pompous fool' and a 'very stupid guy’ who his team would no longer work with.

Mr Edginton, who said he helps run the Brexit Party’s social media feeds, confessed his link to the saga today.

He wrote in the Mail on Sunday: ‘I am not the leaker – I am a young journalist – but I did play a critical role in the publication of a story that has reverberated on both sides of the Atlantic.’

He continued: ‘The political storm in which I now find myself is a world away from where this began for me five years ago.

‘I started posting videos about politics on YouTube when I was 14 and a student at a state school in Portsmouth.’

The teenager said the story was not a ‘Brexiteer plot to topple Sir Kim’ but was ‘simply an honest journalistic endeavour’ after seven months of investigations.

He turned to journalist Isabel Oakeshott to help break the story on the front page of the Mail on Sunday, but claims to have omitted his byline because of ‘possible controversy’.

Scotland Yard announced a criminal investigation after the letter was leaked to the press amid allegations of breaches of the Official Secrets Act.

Addressing the probe, Mr Edginton said: ‘These cables did not contain any state secrets. Sir Kim was simply articulating what many in Washington and Whitehall have said about the president and his advisers since he took office.'

The teenager previously worked as a video journalist for the political website Westmonster, before turning to digital strategy at the Taxpayers' Alliance and Leave Means Leave campaign.