Freedom campaigners for a refugee held in a notorious US prison camp have pledged to keep fighting for his release.

Omar Deghayes, from Brighton, has been imprisoned at Guantanamo Bay in Cuba for four and a half years without being brought to trial.

Members of the Save Omar Campaign said they were frustrated by inaction from the British Government but vowed to keep pressing for his return to the UK.

A conference, called Omar Deghayes: Brighton's Man in Guantanamo Bay, was held at Brighton University on Saturday about the cause and to rally support.

Leading speakers on human rights issues gave talks and there were workshops to plan for the future of the Save Omar Campaign.

A rough cut of a film documentary called The Search for Justice was shown for the first time.

It chronicled the story of Mr Deghayes, a refugee from Libya who moved to Brighton after claiming asylum and was captured on a trip to Pakistan with his wife and baby.

In the film, former prisoners said they had seen photographs of Mr Deghayes in Guantanamo and that he looked like he had "been beaten up pretty badly".

One witness said: "His face was gaunt, he had been battered and was bruised and clearly had a very rough time of it."

He said Guantanamo Bay was a hopeless place and many inmates did not know why they were being held there.

The witness added: "Guantanamo Bay is a complete black hole, a legal limbo of incarceration of which there is no way out."

Jackie Chase, of the Save Omar Campaign, said volunteers had been frustrated by the apparent lack of results, adding: "We have achieved nothing."

She said a major problem was the British Government's refusal to represent Mr Deghayes because he was not a UK citizen and only had residential status.

It is feared Mr Deghayes, 37, would be killed if he was released back to his native Libya, which he fled because his father was tortured for being a trade unionist.

Abdel Malek, president of Libya Watch, said: "If we don't fight for the freedom of Omar, we may have to do it for our own children in the future.

"The whole bastion of democracy that we have built will crumble around us."

Louise Purbrick, also of the Save Omar Campaign, said they would keep working for Mr Deghayes' release back to the UK.

She said the next step would be a Free Omar Walk to ask Foreign Secretary Margaret Beckett personally for help.

The walk, which will be made in relay groups, leaves Brighton on December 15 and is due to arrive in London on December 21.

Other conference speakers included writer and broadcaster Craig Murray and former Guantanamo Bay detainee Mozzam Begg.

The Argus is supporting calls for Mr Deghayes' release with its campaign Justice For Omar.