The Transport Agency has apologised for an error that led to a convicted child sex offender becoming a school bus driver.
The agency's spokesperson Andy Knackstedt says serious human error is to blame for the approval of a bus licence for 72-year-old Maurice Cudby in May 2010.
Cudby was imprisoned in 1993 for molesting girls at a rural school while he was principal and was imprisoned again last month for similar offences against a boy.
Mr Knackstedt says the staff member who made the error had a copy of Cudby's criminal convictions, but approved the licence anyway.
He says he is unable to find out why this happened because the staff member no longer works there.
He says other applications the person granted are currently being investigated, but he believes this is an isolated case.