Two Britons and a Canadian who say they were tortured in a Saudi jail can pursue legal costs against the Saudi government, the Appeal Court says.
Mr Mitchell was sentenced to a public beheading
In October, Sandy Mitchell, Les Walker and Bill Sampson won the right to sue Saudi officials in UK courts, with an order the Saudi state pay their costs.
However, the Saudi government has refused to pay the costs and will now take the case to the House of Lords.
The court said Saudi state assets could be seized to cover the costs.
On Monday the Appeal court rejected the trio's application that Saudi could not claim state immunity to avoid paying, the lawyers said.
If commercial assets in the UK - such as planes - are seized by the High Court sheriff, Saudi Arabia could apply for state immunity from such a measure.
It had agreed not to appeal the court order to pay the men's legal costs, but the amount - about £100,000 including interest - has not been handed over.
Mitchell, Walker and Sampson, a Canadian, say they were tortured and forced to confess to bombings in Saudi Arabia.
They spent two and a half years in prison after being convicted of a series of bombings in the country.
Mitchell and Sampson were sentenced to a public beheading and crucifixion, but were among five Britons released by Saudi's King Fahd in August 2003.
They want compensation from two of their interrogators, the prison deputy governor and a government minister and have made a claim in the High Court for damages.
The five Britons 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.
Tamsin Allen, of Bindman & Partners, which acts for the men, said of Monday's court decision: "We, our clients and the public funding authorities are outraged Saudi Arabia, one of the richest states in the world, should force the hard-pressed legal aid board to pay its debts and at the same time use our courts to seek immunity from torture claims.
"We will enforce the demand through the High Court in the same way as we would enforce any debt, by asking the sheriff to seize sufficient commercial property to satisfy the debt."
A spokesman from the Saudi Arabian embassy said: "We would like to point out that the three Court of Appeal judges did 'not need to trouble' the lawyers representing the Kingdom of Saudi Arabia before dismissing the application before them."
He added that the men's lawyers "had not taken steps to enforce the order from last year and the amount had not even been decided until 31 March this year."
The case is due to be heard in the House of Lords on 26 April 2006.