Staff at the centre were also alleged to have used inappropriate restraining techniques, including one case where a teenager had their windpipe squeezed so hard he couldn't breath properly G4S

Seven members of staff at a young offenders centre run by private security contractor G4S have been suspended over a series allegations of abuse against children. Police are investigating claims teenagers held at Medway Secure Training Centre (STC), near Rochester, were punched and repeatedly slapped on the head.

Staff at the centre were also alleged to have used inappropriate restraining techniques, including one case where a teenager had their windpipe squeezed so hard he couldn't breath properly. The allegations were reported in The Times today (8 January) but were said by G4S to have stemmed from an upcoming BBC Panorama programme in which hidden cameras were smuggled into the centre. The alleged abuse is understood to have taken place in the autumn.

Police in Kent have begun an inquiry into the allegations and staff members at the centre, which holds 76 people aged 12 to 18, were suspended last month. The allegations will raise serious questions over whether the company is fit to manage the other youth training centres, children homes, and prisons it runs across England and Wales.

Staff were also alleged to have boasted of mistreating young people at Medway STC, including stabbing one in the leg with a fork and of making another cry uncontrollably. Staff tried to conceal their misbehaviour, according to The Times, by ensuring that they were concealed from the centre's CCTV, or in areas not covered by cameras.

It represent just the latest in a number of setbacks for the public face of G4S, which is the world's largest private security contractor. The company was investigated in 2013 over allegations it overcharged for tagging criminals in the UK, which resulted in the company paying the government £109m.

In February 2015, the contractor faced a damning Ofsted report following an inspection at the G4S-run Rainsbrook youth training centre near Rugby. Children held there were found to have been subject to "degrading treatment" and racist abuse by staff under the influence of illegal drugs.

G4S was awarded a £50m five-year contract to run Medway STC last September. In the most recent Osfted inspection, in 2014, Medway STC was classified as "good with outstanding features".

Paul Cook, managing director for G4S Children's Services in the UK, said the allegations had been referred to Medway's Local Authority Designated Officer for safeguarding children (LADO), the Youth Justice Board (YJB) and the Ministry of Justice (MoJ).

He 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 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."

A Kent Police spokesman said: "Following a referral from the Medway Local Authority Designated Officer, Kent Police is investigating allegations that have been made regarding reports of abusive behaviour (physical and verbal) at a secure training facility in Medway. All necessary safeguarding measures have been taken and enquiries are ongoing."