Detained: Michael Sandford is taken from the Trump rally after allegedly trying to snatch a gun

A Tory MP has vowed to ask Boris Johnson to intervene in the case of a Briton accused of trying to kill Donald Trump.

Sir Paul Beresford is to raise the plight of Michael Sandford with the new Foreign Secretary after he was approached by the Sandford family.

They are hoping to have their son deported from a US jail to Britain to be given the psychiatric treatment they believe he desperately needs.

Mr Sandford is due to face trial in August for allegedly trying to snatch a policeman’s gun at a Trump rally in Las Vegas last month.

The 20-year-old, who suffers from autism, told police he travelled to the city to kill Mr Trump, according to court documents.

His family has secured the services of the top lawyer who successfully represented Pentagon hacker Gary McKinnon, who also suffers from autism.

Mr McKinnon hacked into Nasa and security service computers from a house in London, leading American authorities to demand he face a US court and possible life imprisonment.

But lawyer Karen Todner fought a ten-year battle to stop Mr McKinnon from being extradited, and the move was finally blocked by the then Home Secretary Theresa May in 2012.

Ms Todner was concerned about the treatment Mr Sandford might experience in prison in America, but added there was a chance he could serve any sentence he receives in the UK under an existing agreement with the US.

She said: ‘There is a provision under the repatriation and transfer of prisoners treaty, but Michael needs to enter into a plea arrangement for there to be any chance of getting him back to the UK. There are similarities with McKinnon’s case but the real difference is he was in the UK and Michael is not. Michael has a long history of mental illnesses. He needs to be bought back here to be cared for as quickly as possible.’

Last night, Michael’s mother Lynne said: ‘The Foreign Office told me someone went to visit him earlier in the week and said he was not in a good way.

Announcement: Donald Trump yesterday with Indiana governer Mike Pence, who was named his presidential running mate. Mr Sandford old police he travelled to the city to kill Mr Trump, according to court documents

‘He is now on suicide watch in a padded cell and on three strong pills – one for hallucinations, one for anxiety and one for sleeping.

‘He is being kept in isolation and I can’t even speak to him let alone see him. It’s heartbreaking.’

At the Republican rally in Las Vegas on June 18, Mr Sandford allegedly told a police officer he wanted Mr Trump’s autograph before trying to grab the officer’s gun. In a police interview he told detectives he was ‘trying to shoot and kill Donald Trump’.

Days later, a confused-looking Mr Sandford, from Dorking, Surrey, was paraded in handcuffs and leg irons in a county court.

Last week he pleaded not guilty to one charge of disrupting business and official functions, and two charges of being an illegal alien in possession of a gun. If found guilty he faces up to 30 years in prison.