Paul Reeve. Worked at Hewett school, Norwich. On sex offenders' register after being cautioned by police for accessing websites containing child pornography.
Kim Howells, former education minister, cleared him to work in schools.
Reeve has now resigned.
William Gibson. Worked at Portchester school, Bournemouth. Convicted in 1980 for indecently assaulting a 15-year-old pupil in Sunderland. He said they went on to have a genuine relationship.
Gibson previously worked at St Joseph's RC comprehensive in Hebburn, South Tyneside, for three months in 2003 and at Hebburn comprehensive for a day in October 2004. He also taught for a day in a school in County Durham.
He is not on List 99 or the sex offenders' register.
Keith Hudson. The Sussex teacher was convicted of possessing indecent images of young boys. He was put on List 99 in 2001 with a direction from Estelle Morris, the then education secretary, which cleared him to work in an all-girls school.
Stephen Woodcock. Never convicted of an offence. Banned from teaching in 2001 after it was alleged he touched a pupil in a way so distressing that the child ran out of the classroom. Twelve allegations had previously been made against him by 10 boys from 1987 to 1992. He resigned following these allegations but the Department for Education and Skills decided at the time not to put him on List 99.
Steven Taylor. Convicted in December 2005 of the rape an 11-year-old girl in 2001. The primary teacher met the girl when he had a short-term contract at her school. He was given an eight-year jail sentence and is now on the sex offenders' register.
Mr Taylor had previously been identified by Essex County Council as unsuitable for teaching on the authority's List 98, but was not on the national List 99.
Convicted of molesting a 12-year-old boy by pulling down his swimming trunks. Banned from teaching other than at further education institutions in 1998, by David Blunkett, then education secretary.
The Care Standards Tribunal overturned that ruling and said he could teach in schools where all pupils were over 14.
Sacked for writing "inappropriate words" in the condensation on the window of his prep school flat about a pupil. He was barred from teaching.
In 2001 a tribunal allowed him to return to teaching but restricted him from living on a school site or having any pastoral role.