Britain's last remaining Guantanamo Bay detainees landed back in the UK just after 5pm today and were immediately arrested.
The four men were accompanied by Metropolitan Police Anti-Terrorist Branch officers and medical and RAF police personnel when they landed at RAF Northolt in west London.
Two independent observers, one from the Muslim community, were also on board.
It was thought likely the four would be taken to the high-security Paddington Green Police Station in Central London for questioning.
There had been calls for the men to be given medical attention and quickly released when they landed.
The four are Moazzam Begg from Birmingham; Feroz Abbasi from Croydon, south London; Martin Mubanga from Wembley, north west London; and Richard Belmar from St John's Wood, north west London.
Five British men released from Guantanamo Bay last March were held for just a few hours for questioning by police before being freed without charge.