Just weeks after footage emerged of staff appearing to use excessive force on young inmates, G4S has announced it is selling its children's services business.

The security firm today confirmed that as part of its "on-going review of its portfolio of businesses" it will sell its UK Children’s Services business, comprising 13 children’s homes and its contracts to manage two Secure Training Centres at Medway and Oakhill.

Andrew Neilson, Director of Campaigns at the Howard League for Penal Reform, said they welcomed the news.

He said: "These child jails have been the focus of much controversy, not least the recent BBC Panorama documentary into abuse by staff at Medway.

"There is now an opportunity developing to close the secure training centres down completely. These centres are a failed model and this wise withdrawal from the market by G4S should not be followed up new private security companies coming in to replace them, with dubious track records abroad in the treatment of people in custody."

The news comes as figures showing that no children were injured while being restrained by staff at Medway Secure Training Centre are being questioned by the Ministry of Justice.

An investigation is under way after the Medway Messenger asked the department about the data which was supplied by G4S, the private security firm who run the Rochester centre.

It comes after footage secretly filmed for Panorama by an undercover journalist showed staff appearing to use excessive force to restrain youngsters, children being bullied by staff, officers lying when reporting incidents and staff boasting about hurting inmates.

An MoJ spokesman said: “We are investigating the accuracy of all restraint injury data from Medway Secure Training Centre. This independent data was provided to the Youth Justice Board by G4S.”

The figures, which were published after the issue was raised in parliament, reported that no young people were injured during what is termed restrictive physical intervention (RPI) in 2014. In 2008 there were 331 injuries reported.

The number of young people reportedly injured in assaults increased from just one in 2008 to 40 in 2014 – five of which were serious injuries.

There was only five reports of injuries to staff during RPIs over the six years.

The number of reported self harm injuries also declined from 186 in 2008 to nine in 2014. Data for 2015 is not yet available.

Following the programme Paul Cook, managing director for children’s services at G4S, said he was “appalled” by the behaviour of certain members of staff and said they were conducting an internal review.

The MoJ spokesman added: “As the Justice Secretary said last month, the safety and welfare of all those in custody is vital.

“That is why an independent improvement board has been appointed to provide increased oversight, scrutiny and challenge of managerial arrangements at Medway, in particular in relation to safeguarding of young people.”

The board is being chaired by Dr Gary Holden, chief executive of academy provider The Williamson Trust, and the principal of the Rochester Math School, which is less than a mile from Medway STC.

Managing director for G4S children’s services, Paul Cook, said: “After every incident of restraint, young people are seen by a member of the healthcare team and every use of force is examined by a multi-agency group including the Youth Justice Board Performance Manager, the NHS Healthcare Manager, Centre Director and where possible representative from the Local Authorities Children’s Services.

“These data on injuries following restraint are collected and recorded independently by the on-site healthcare team, and our team of frontline custody workers are not involved in the reporting of this information.

“We continue to support the work of the newly appointed Ministry of Justice Improvement Board to address the very serious issues raised at the Medway secure training centre last month.

"The Ministry of Justice is also conducting a thorough audit of reporting practices at all three secure training centres and we are cooperating fully with this process.”

After the BBC Panorama programme, three men from Medway, aged 25, 34 and 35, have been arrested on suspicion of child neglect. A Medway man, 28, was arrested on suspicion of assault, and a 25-year-old East Sussex man was arrested on suspicion of child neglect. They have been bailed until April.