“You’ve got to have the urge to punch him in the face.” “If he dies, he dies.” From some of the officers, whose comments were picked up by Callum’s hidden microphone at different times, there is no sympathy - even the threat of violence - towards the people in their charge. “With a lot of the officers, you do see them become desensitised. It just becomes the norm,” Callum says. “People can’t cope and hand in their notice, but others become immune to the pain and suffering they see. Some turn to the other side and take part in the abuse.” He says there is a group of officers in Brook House who are bullies, even boasting of hurting detainees. Nathan Ward has been a priest for two years. He used to be a senior G4S manager. He says he warned the company about the attitude of some officers three years ago.

Nathan Ward

“The vast majority were good, decent people,” he says. “But there was a group that actually concerned me on their relationships with detainees. It was around language that they used, a sense of roughness and the use of force - how force was used.” Callum’s camera picks up an incident, which is the most distressing treatment of a detainee that he sees during his time undercover.

A man, who we will call Abbas, is in Brook House after being held on remand in prison. He has been on suicide watch for two days because he was trying to harm himself.

Abbas was on suicide watch

The 20-year-old has already had to have a mobile phone battery removed from his mouth, and while Callum watches over him, he starts trying to choke himself with his own hands. Callum calls for assistance and other officers rush in to stop the desperate man from harming himself. But one officer didn’t just restrain him. “This officer comes in and just chokes him basically. He just exerts all his pressure on from his hands and arms on to this guy’s neck, and you see his eyes roll back. You see his eyes roll to the back of his head,” says Callum. Callum tells the officer he needs to ease off, and the man being restrained is eventually calmed down and released from the hold. When force is used, officers are meant to fill out forms explaining what has happened. It allows managers to review incidents and consider what lessons need to be learned. But in this case the restraining officer makes it clear to those who witnessed what happened that this should not be written up as use of force. The officer involved later told Panorama that he couldn’t think of anything he had done that would get him into trouble. He has since been suspended. In response to the Panorama allegations of mocking and abusive behaviour by a number of staff, G4S says it has suspended nine people and put five others on restricted duties. A former G4S employee, who now works for the Home Office, has also been suspended. G4S says it will take “appropriate action” once it has seen the evidence and continues that any such “behaviour is not representative of the many G4S colleagues who do a great job often in difficult and challenging circumstances”. It also says it investigates all complaints and has confidential whistleblowing channels for staff and detainees.