Shocking scenes in an undercover documentary show a 14-year-old boy being restrained by up to four male officers at a youth custody centre.

The BBC Panorama programme, which aired tonight, was shot at Medway Secure Training Centre.

The opening footage shows a boy called Billy stopping an officer from getting inside a classroom.

When the officer does gain access, he grabs Billy and restrains him in a head lock, with his fingers on his throat.

"The allegations involve matters such as slapping a teenager several times in the head, using restraint techniques, squeezing a teenagers windpipe so as to cause problems with breathing, boasting of the mistreatment of young people including using a fork to stab one in the leg" - Shadow justice minister Andy Slaughter

It takes up to four officers eight minutes to get Billy back in his cell.

Subsequent scenes show a number of similar incidents. The programme also includes footage of staff boasting about hurting youngsters.

Earlier today shadow justice minister Andy Slaughter said all G4S run prisons and centres should be placed into special measures following the investigation.

Mr Slaughter also said G4S should not be considered for further contracts following a number of failings, adding: "We ask that the government takes immediate action to puts all G4S run prisons and detention centres into special measures to assess the safety and competence of their operation."

The BBC Panorama programme was filmed at Medway Secure Training Centre in Rochester between October and December last year.

Seven employees have since been suspended, it emerged on Friday.

Calling for a full independent investigation in parliament, Mr Slaughter said: "The allegations involve matters such as slapping a teenager several times in the head, using restraint techniques, squeezing a teenagers windpipe so as to cause problems with breathing, boasting of the mistreatment of young people including using a fork to stab one in the leg.

"And equally seriously matters such as concealing their behaviour deliberately by doing it out of the sight of CCTV and covering up violent incidents to avoid investigation and the possibility of sanctions against G4S."

"The director of the charity Inquest, Deborah Coles, said that in any other setting this treatment would be child abuse, and this points to a lack of accountability and a culture of impunity."

Justice Secretary Michael Gove said it would be wrong to preempt a police investigation, which was now underway.

However, he said prison inspectors and Ofsted representatives had visited the prison today and spoken with inmates; and that the role of Youth Justice Board monitors and the charity Barnardos would be enhanced at the site.

The Rochester centre, run by private security firm G4S, looks after 76 boys and girls aged 12 to 17.

Reports claim staff punched a youngster in the ribs and another was slapped several times on the head.

Staff are also alleged to have pressed heavily on the necks of young people and one youngster was restrained by squeezing his windpipe so he had difficulty breathing. It is also claimed staff used foul language to intimidate the youngsters.

“Clearly this type of alleged behaviour has no place in any of our institutions. The allegations relate to staff hurting children, the use of foul and abusive language and the cover up of incidents" Paul Cook, G4S

Staff are said to have tried to cover up the mistreatment by ensuring they were not seen by the centre’s 87 CCTV cameras.

The allegations have emerged after an undercover journalist for BBC's Panorama programme went into the centre. The matter is now being investigated by Kent Police and Medway Council’s safeguarding children team.

The BBC describes the programme as: "BBC Panorama goes undercover to expose harrowing evidence of children and young people being hurt and threatened by custody officers who are supposed to protect them.

"Secret filming at a privately run youth prison, paid more than £10m in 2015 by the government to provide high-quality education and to rehabilitate some of the most vulnerable youngsters in the prison system, reveals some officers mistreating their charges and many more tolerating the behaviour or even helping to cover it up."

In a statement, G4S children’s services said it has referred a number of serious allegations of inappropriate staff conduct, centred around the unnecessary use of force and the use of improper language, to the Youth Justice Board and the Ministry of Justice .

Paul Cook, managing director for G4S Children’s Services said he was shocked and appalled by the allegations.

He added: “Clearly this type of alleged behaviour has no place in any of our institutions.

“The allegations relate to staff hurting children, the use of foul and abusive language and the cover up of incidents.

Mr Cook said when the allegations emerged at the end of last year, the matter was immediately referred to Kent Police and Medway Council’s safeguarding children team, who are now carrying out an investigation.

The seven members of staff – all male, were immediately suspended. They include one assistant, four team leaders and two managers.

The alleged abuse is reported to have happened between October and December last year.

Mr Cook said: “We are treating the allegations with the utmost gravity and have taken immediate action to suspend a number of staff members who are alleged to have conducted themselves in a manner which is not in line with our standards.

“We take any allegations of unacceptable or inappropriate behaviour extremely seriously and are giving our full support and co-operation to the LADO [Medway’s Local Authority Designated Officer for safeguarding children] and the police as the investigation moves forward.”

“The Police and LADO are the appropriate independent authorities to conduct the initial investigation into the allegations and once that investigation has concluded, we will agree with the Ministry of Justice and Youth Justice Board whether further independent review or investigation is required.”

“We continue to focus on the care, wellbeing and education of the young people at the centre, which is our primary objective.”

While the investigation is carried out, the centre is no longer accepting any new admissions.