Two actors and the former Guantanamo Bay detainees they play in a new film were stopped by police at an airport under anti-terror laws.
They were held at Luton Airport after returning from the Berlin Film Festival where The Road to Guantanamo had won a Silver Bear award, said a human rights group on behalf of one of the actors.
The Michael Winterbottom-directed drama is about the lives of three men from Tipton who were detained at the United States military base in Cuba.
Released in Britain next month, the film shows the alleged shackling, torture and other ill-treatment which Ruhal Ahmed, Asif Iqbal and Shafiq Rasul claim they suffered.
Human rights group Reprieve said Mr Ahmed and Mr Rasul and the actors who played them - Rizwan Ahmed and Farhad Harun - were "detained" at the Bedfordshire airport last Thursday after returning from Germany.
Bedfordshire Police said four people from a party of six had in fact been stopped and spoken to on arrival at Luton Airport under the Prevention of Terrorism Act.
A man was stopped first by Special Branch officers having passed through immigration and three others travelling with him were stopped shortly afterwards.
The two remaining people in their party had already passed through the airport.
The four men were invited to a nearby room where their identities were confirmed and questions about their journey and reasons for travelling established, said police.
No further police action has been taken.