BRITAIN'S last remaining Guantanamo Bay detainees were in custody again last night after being arrested by anti-terrorist police on their return to the UK.

Shortly after the four landed at RAF Northolt in the early evening they were arrested by officers from SO13 while still on board the aircraft.

As suspected terrorists, the men had been in legal limbo at the US naval base on Cuba for up to three years.

Moazzam Begg from Birmingham, Feroz Abbasi, Martin Mubanga and Richard Belmar, all from the London area, were last night being held under Section 41 of the Terrorism Act 2000.

It refers to the "alleged involvement in the commission, preparation or instigation of acts of terrorism".

They will be medically examined before being interviewed by anti-terrorist officers. They will also be allowed a phone call and a visit by a family member, and have access to a solicitor of their choice.

Peter Clarke, deputy assistant commissioner and head of the Anti Terrorist Branch, said:

"We recognise that there are strong feelings about the return of these men to the UK.

"But the fact is that we have an absolute duty on behalf of all communities to investigate the circumstances leading to the men's detention."

The four men were taken in armoured police vans to the high-security Paddington Green police station where protesters had gathered.

Massoud Shadjareh, from the Islamic Human Rights Commission, said: "After three years of torture and questioning, even the Americans have concluded they are innocent . . .

What sort of homecoming is this?

"They are innocent people."