One can be forgiven for being confused over what has happened to the three men returned to Britain from Guantanamo Bay on Tuesday night.

Two of them — Omar Deghayes, 37, and Abdelnour Sameur, 34 — were arrested under the Terrorism Act 2000 and are being held at Paddington Green high security police station for questioning. It is an indication that Scotland Yard’s Counter-Terrorism Command wants to be certain they pose no threat to Britain before releasing them.

Most of the previous returnees from Camp Delta have been through the same process and none have been involved in any trouble since they came back.

The third man, Jamil el-Banna, 45, was detained under port and border controls — a signal that Britain does not regard him as posing any serious security threat.

Unlike the other two men, Mr el-Banna had not been anywhere near Taleban-controlled Afghanistan. He had been picked up by the CIA in Gambia after MI5 alerted the Americans to his arrival there in November 2002.

Yet it is Mr el-Banna who Spain has targeted with an extradition request, causing him to be arrested and brought to court. He may yet face a terrorist trial in Madrid.

At the core of the allegations against Mr el-Banna is his association with Abu Qatada, the jailed extremist cleric. That same link led MI5 to try and recruit Mr el-Banna as an informer.

Spain alleges that Mr el-Banna had links with a Madrid al-Qaeda cell that recruited young men and sent them for jihad training. That cell is said to have had ties to the German-based al-Qaeda unit that plotted the September 11 atrocities.

What has motivated Spain to act now is something of a mystery. America has had Mr el-Banna in custody for five years and interrogated him repeatedly in brutal conditions. It laid no charges against him and deemed him fit to be freed. Spain made no attempt to extradite him from or question him while he was in US custody.

The British Government has been asking for and negotiating Mr el-Banna’s release and had no intention of putting him on trial as a terrorist when he returned here.

Spain’s action seems inhumane and its evidence rather thin. But the use of the European Arrest Warrant means Britain had no choice but to arrest a man who has just spent years isolated in America’s notorious internment camp.

A judge granted him bail early this afternoon, but Mr el-Banna’s fight against extradition to Spain is only just beginning. It seems likely that another of the returned detainees is also to face the threat of extradition to Madrid on the basis of even more flimsy evidence.

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