Lawyers for Guantanamo Bay detainee Omar Deghayes will submit an appeal against their High Court loss by the end of the week.

Birnberg Peirce and Partners, representing Mr Deghayes and two other British residents at the jail, hope the Court of Appeal will overturn last week's High Court ruling that judges were powerless to order the Government to request their release.

Mr Deghayes' lawyers insist the Foreign Secretary has a legal and moral duty to intervene in the case of Mr Deghayes, 37, from Saltdean, who has been held at Guantanamo for almost four years. He has been a British resident for more than 20 years and his mother, brothers and sister are all British citizens.

They fled Libya in the Eighties after Mr Deghayes' father was assassinated and they were all granted refugee status by the UK.

But the High Court judges said foreign policy was "a forbidden area" for the courts. The case for UK intervention was very strong, but there was no duty in domestic or international law which required it.

Meanwhile, a letter to Argus group editor Michael Beard from Foreign Office minister Kim Howells said the Government had raised issues of detainees who were former British residents.

In a reply to a letter sent by Mr Beard at the end of March, Mr Howells said: "We regard the circumstances under which detainees continue to be held at Guantanamo Bay as unacceptable. The US government knows our views."

He refused to comment on Mr Deghayes' case as it was the subject of legal proceedings. Meanwhile people are being urged to write to new Foreign Secretary Margaret Beckett asking her to intervene.

The Argus is campaigning for the trial or release of Mr Deghayes. If you want to write to the Foreign Secretary, send your letters to Miriam Wells at The Argus, Crowhurst Road, Brighton BN1 8AR or direct to the Foreign and Commonwealth Office, King Charles Street, London SW1A 2AH.

For a sample letter to copy, email saveomar@yahoogroups.co.uk .