Two Britons who say they were tortured and forced to confess to bombings in Saudi Arabia are to sue for compensation, say their lawyers.
Mr Mitchell's sister said he often wakes up screaming in the night
Sandy Mitchell and Les Walker spent two-and-a-half years in prison after being convicted of a series of bombings in the country.
The pair want compensation from two of their interrogators, the prison deputy governor and a government minister.
They were among five Britons released by Saudi's King Fahd in August 2003.
Lawyers acting for Mr Mitchell and Mr Walker said the two and a fellow inmate, Canadian Bill Sampson, have made a claim in the High Court for damages.
Les Walker managed a housing compound for British Aerospace
The five men, who also included James Cottle, James Lee, Peter Brandon were jailed for a series of bombings that killed one Briton, Christopher Rodway, in November 2000, and injured several other Western expatriate workers.
Mr Cottle, Mr Lee and Mr Brandon and a sixth Briton Glen Ballard - held for 10 months but not charged - are also pushing for damages through a law firm in Manchester.
The five men were among seven men convicted, including a Belgian national and Mr Sampson.
Saudi authorities claimed the bombings were part of an alleged feud over illicit alcohol trading among expatriates.
Mr Mitchell, from Kirkintilloch, near Glasgow, and Mr Sampson were sentenced to a public beheading and crucifixion.
One of the torture techniques the interrogators are said to have used is hanging inmates for days in positions which prevented sleep.
In September Mr Mitchell told the BBC's Frontline Scotland programme he was punched, kicked, spat on, beaten with sticks and hit on the soles of his feet with an axe handle. His sister said he often woke up screaming in the night.
He said when first taken into detention in Saudi he was told: "You will confess or you will go insane with what we're going to do to you."
Both Mr Mitchell, 48, and Mr Walker, 51, of Neston, the Wirral, said they had contemplated suicide.
The recorded video confessions were broadcast by the Saudi authorities and screened internationally.
Last year Saudi authorities told the BBC they stood by their claim the men's crimes were part of an alcohol smuggling feud, and denied torture.
The men's lawyers say specialist medics can confirm the three were tortured.
The lawyers said they would be seeking to clarify whether any of the men were pardoned before the Saudis freed them, a question which remains unclear.
The three are making a claim against their prison interrogators Lieutenant Khalid al-Salah and Captain Ibrahim al-Dali, Colonel Said, the deputy governor of al-Ha'ir prison, and the Saudi minister of interior Prince Naif bin Abdul Aziz.
Mark Emery, a solicitor at Bindman and Partners would not say how much money is being sought.
He added it was "certainly possible" the men would go on to sue the state of Saudi Arabia.
A joint statement from the law firms representing all seven men said: "Since September last year the Saudi government has rejected requests to acknowledge
the undoubted innocence of the men and their appalling mistreatment in Saudi