Pressure has increased on the home secretary to intervene in the case of a former soldier who is facing extradition to America over fraud allegations despite being deemed a suicide risk.

David McIntyre, 41, who served in Afghanistan, was told on Friday he could not take his appeal to the UK Supreme Court, despite presenting medical evidence that showed he is suffering from an untreated post-traumatic stress disorder (PTSD).

david mcintyre extradition

David McIntyre insists he is innocent and doesn't believe he will receive a fair trial in the USA

Keith Vaz MP, the chair of the influential Commons Home Affairs committee, has written to Theresa May urging her to take the condition into account and to respond to a previous letter from Mr McIntyre's constituency MP, Jonathan Reynolds.

Mrs May has already given Mr McIntyre, who served with the Queen's Lancashire Regiment and Royal Military Police, until 9 April to present her with further medical evidence on his medical condition.

Mr Vaz said: "I am troubled by David's case and would like to thank his MP Jonathan Reynolds for bringing it to my attention.

"I have written urgently to the home secretary and asked for her assurance that she will fully consider any new medical evidence put before her, before considering whether or not Mr McIntyre should be extradited.

"The Committee has called for an overhaul of the unfair and unbalanced UK-US extradition treaty and I will be putting this case before them tomorrow.

"It is my view that ministers should exercise their discretion in extradition requests concerning British citizens."

In his letter, Mr Vaz refers to the case of Gary McKinnon, the so-called "hacker" whose extradition to the US was blocked by the government.

The Americans have accused Mr McIntyre, who served with the Queen's Lancashire Regiment and Royal Military Police, of overcharging a US peace group for a security contract when he was running his own firm - charges he denies.

Mr McIntyre, who faces a 20-year jail sentence if he is extradited to the US, said: "In my life, I've always looked after people and now I can't look after myself. It's tearing me apart.

"My life is going to be over. If I get sent to the US, I'm going to lose everything."

Mr McIntyre served in the Territorial Army before joining the Queen's Lancashire Regiment in 1996. He served in Bosnia and Northern Ireland.

He left in 2002 and set up security company Quantum Risk, which employed a team of 20 to provide security to American clients, including the Iraqi ambassador to the US.

The business ended in 2009 and Mr McIntyre enrolled in the Royal Military Police, for whom he served in Afghanistan.

It was last July when the US charges emerged and the soldier was flown back from Camp Bastion, in Helmand Province, to face extradition proceedings.

Mr McIntyre faces eight counts of fraud concerning a contract with the United States Institute of Peace (USIP). It is alleged he overcharged the organisation by $100,000 (£65,000).

He said: "I'm not a rich guy. If I had any money, I wouldn't have volunteered to go and face getting killed in Afghanistan.

"I know I'm innocent but I also know I won't get a fair trial. I'll be shackled in chains, put on a plane and locked in federal penitentiary with the real bad guys."

Mr McIntyre's appeal was dismissed in February before he had presented the court with a report from the British Army's consultant psychiatrist confirming he suffers from PTSD and warning that if he is extradited he could react "impulsively, dangerously and potentially tragically".

Mr McIntyre's legal team, who also represented Gary McKinnon, attempted to present the medical report to the High Court on Friday but were told it was too late to be considered.

He said: "I thought the British justice system would support me rather than throw me to the wolves."

The former soldier believes he is the victim of a plea bargain in which a US official, accused of similar offences, named him to secure a lenient sentence.

Mr McIntyre said he has been suffering from the severe anxiety disorder for many years but kept it private. He said the extradition proceedings have worsened the condition and brought it to the fore.

He said: "It's seen as a sign of weakness. You don't want people to think you're a fruitloop.

"It manifests itself in different ways. I've seen some terrible things. There was a time in Baghdad when we were smashed by shells every single day for about six or seven weeks.

"I recall taking a break from Iraq in Dubai. I was stood in my hotel room and the door blew shut. I jumped under my bed. I was terrified."

He added: "When I returned from Afghanistan, I felt really down and I did think about self-harm. I got through that."

A Home Office spokesman said: "David McIntyre is wanted in America in connection with fraud allegations.

"On 22 March the Court of Appeal rejected his appeal against extradition and he was refused leave to appeal to the Supreme Court.

"We have agreed to suspend extradition pending further representations to the secretary of state from Mr McIntyre's solicitors."