Sandy Mitchell has been sentenced to death

The sister of a Scottish man facing the death penalty in Saudi Arabia has accused the Foreign Office of not treating the case as a priority.

Margaret Dunn said she was now certain that Sandy Mitchell was going to die.

The 44-year-old was convicted of being part of a bombing campaign which killed two people in the capital Riyadh.

Mr Mitchell and Glasgow-born William Sampson face public beheading.

Four other Britons are serving 12-year sentences for plotting the bombings in an alleged feud over illicit alcohol trading among expatriates.

We all live our life sitting waiting for the telephone call that never comes Margaret Dunn

Mrs Dunn has broken her silence to speak to the BBC's Frontline Scotland programme.

"I was told that this was a priority and I believed them," she said.

"For two-and-a-half years I have said nothing and waited for the Foreign Office to do their job.

"I am certain that this isn't high priority any more and that Sandy is going to die."

Mrs Dunn has met Foreign Secretary Jack Straw, but said he had failed to convince her that the case was a priority.

"If he cannot convince me, how can I expect him to convince the Saudi authorities that this was top priority of the British Government," she said.

Coming home

"I came out feeling probably worse than I did when I went in."

Mrs Dunn said that she wanted to know the truth about whether or not her brother would be coming home.

"We all live our life sitting waiting for the telephone call that never comes," she added.

Margaret Dunn discussed the case with the foreign secretary

"Sandy's little boy Matthew is growing up without his daddy. He thinks his daddy is a man in a picture.

"If you ask him where his daddy is, he just says my daddy's gone."

Mr Mitchell, from Kirkintilloch near Glasgow, is one of three men who appeared on Saudi television in February 2001 confessing to their part in the bombing campaign.

The friends and families of the six Britons being held claim that the confessions were false and that the motive given by Saudi authorities had been "concocted".

They have argued that Monday's triple suicide bombings in Riyadh, which left at least 34 people dead, supported their claims.

Labour MP John Lyons highlighted Mr Mitchell's case in the Commons this week.

BRITONS JAILED Sandy Mitchell, Glasgow William Sampson, Glasgow / Canada James Cottle, Manchester Les Walker, Wirral Peter Brandon, Wales James Lee, Cardiff Timeline: Britons in Saudi jails

He asked Prime Minister Tony Blair to step up the political and diplomatic pressure for his release.

Mr Lyons argued that after the suicide bombings it was clear that there "must be serious doubts" about the conviction of the Britons.

Mr Blair said that the government was "deeply concerned" about the case.

"We are working vigorously to resolve this case," replied the prime minister.

"We are fully aware of the concerns, but the best thing for the individuals concerned and their families is that we carry on working in the way we have to try to secure their release."

Frontline Scotland's programme Left To Rot will be screened on BBC One Scotland at 1900 BST on Thursday.