Security firm G4S has apologised for overcharging the Government for its provision of electronic tagging services, calling its actions "unacceptable".
The group's chief executive Ashley Almanza said:
The way in which this contract was managed was not consistent with our values or our approach to dealing with customers.
Simply put, it was unacceptable and we have apologised to the Ministry of Justice.
We remain committed to working with the Ministry and the UK Government to resolve this matter and to provide enhanced oversight of service delivery and contract performance.