G4S, the world's biggest security company, is pulling out of running 13 children's homes and two youth jails in the UK after being hit by a series of scandals. The firm said on Friday (26 February) it had started a process to sell its UK children's services business, despite revenues last year of £40m ($55.6m).

The sale will include the running of Medway and Oakhill Secure Training Centres (STCs), while a third centre, Rainsbrook, is currently being transferred to a new operator, MTC Novo.

Prison welfare campaigners welcomed the announcement, calling the centres "a failed model", while Labour's shadow minister for human rights, Andy Slaughter, tweeted: "Welcome news that G4S to pull out of running youth facilities. Labour had called for all G4S facilities to be put into special measures."

The announcement comes just six weeks after an undercover BBC Panorama expose at Medway SCT filmed children seemingly being slapped and punched by staff. Young offenders at the centre, near Rochester in Kent, were also allegedly subject to inappropriate restraining techniques, including one case where a child was said to have had their windpipe squeezed so hard they were unable to breathe.

Seven G4S staff were subsequently suspended and four men later arrested by Kent Police on suspicion of child neglect. Another man was arrested on suspicion of assault.

G4S, which has run Medway since it opened in 1998, said Friday's announcement was part of its "on-going review of its portfolio of businesses". It added: "The well-being and education of the children in our care will remain our priority until such time as an orderly transition to a new operator has been completed. The transfer or sale of certain businesses is subject to customary consents and approvals."

The announcement also comes as the Ministry of Justice probes the accuracy of figures that showed no children had been injured while being restrained by staff at Medway SCT in 2014.

Andrew Neilson, director of campaigns at the Howard League for Penal Reform, said: "We welcome this news from G4S, as the company's sale would include the management of two secure training centres at Medway and Oakhill. 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."