EDUCATION Secretary Ruth Kelly faced renewed pressure last night after a second case emerged in which a sex offender found work in schools.

An aide to Ms Kelly said she was getting on with her job, despite coming under more pressure as details of the North-East case emerged.

The row started when it emerged that her department cleared Norfolk PE teacher Paul Reeve to work, even though he was cautioned by police for downloading child pornography.

The second case relates to William Gibson, 59, who was convicted in 1980 for indecent assault on a child, but later worked at schools in County Durham and South Tyneside.

He was 33 when he started dating a 15-year-old student from the Sunderland comprehensive school where he was teaching.

He was caught when he sent roses to her house and her parents became suspicious.

Mr Gibson, who then lived in South Shields, South Tyneside, admitted indecent assault and was fined £50 and ordered to pay a £10 advocates fee.

In 2000, he was jailed for two-and-a-half years for fraud, forgery and theft.

Like Mr Reeve, it is understood Mr Gibson was not on the Education Department's List 99, containing the names of those banned from working in schools.

In 2003, Mr Gibson taught maths for three months at St Joseph's RC Comprehensive School, in Hebburn, South Tyneside, until his history was uncovered.

Despite being revealed as a convicted sex offender, he was given work in October 2004 at Hebburn Comprehensive. He lasted a day before he was asked to leave.

Less than six months later, the former financial advisor found temporary work at a County Durham school, where he worked for a day before being sacked.

Durham County Council said he was refused employment as a supply teacher in 2002 when police checks uncovered his background.

However, the council later discovered he worked for a day as cover in a secondary school, which was later advised not to re-employ him.

South Tyneside Council admitted he was employed before checks into his past were completed. When they were, he was asked to leave.

Lord Mackenzie, of Framwellgate, a former president of the Police Superintendents' Association and a Home Office advisor, said: "There are dangers with these people slipping through the net and the system needs to be tightened."

Detective Superintendent Mike Jones, of Northumbria Police, said there was a thorough vetting process for would-be teachers.

Margaret Morrissey, of the National Confederation of Parent Teacher Associations, said: "This seems to be a system in crisis."