A female teacher who had a sexual relationship with a 15-year-old girl has been banned from teaching for life.

Suzanne Harrison was a geography teacher at a school in Colchester, Essex, between November 2004 and July 2006.

Between 2005 and 2010 Harrison, now 46, became and remained a close friend of Pupil A's family, a disciplinary panel heard.

In January 2006 while Ms Harrison was minding Pupil A and her sister at her own home a sexual encounter took place between the teacher and the teenage pupil.

Suzanne Harrison (pictured) was a geography teacher at a school in Colchester, Essex, between November 2004 and July 2006

The Teaching Regulation Authority (TRA), said: 'A sexual relationship between Ms Harrison and Pupil A continued for approximately four years thereafter.

'In October 2009, Ms Harrison introduced Pupil A to Ms Harrison's then partner, Person B, who then began a relationship with Pupil A.

'In time Pupil A disclosed the fact of her past relationship with Ms Harrison to Person B.'

The girl's mother and Harrison's ex partner then told police in the summer of 2011 what she had done.

Harrison was arrested and quit her job in July 2011 - and the next month at Ipswich Crown Court admitted four offences of sexual activity with a child and while in a position of trust.

TRA chairman Alison Robb-Webb said: 'The panel noted that the behaviour involved in committing the offence involved the most severe breach of boundaries, not only as a teacher, but also a friend of Pupil A's family.

'Whilst there is no evidence of an effect on the wellbeing of the pupil, Pupil A was brought into a sexual relationship at an age where by law and for her own protection that relationship was criminalised. Ms Harrison's actions involved a double abuse of trust.'

The panel, which met on January 4, this year, said her actions were deliberate.

They also said she had a previous good history and parents, pupils and colleagues spoke warmly of her dedication and skill as a teacher.

But they ruled: 'The findings of misconduct are particularly serious as they include a finding of sexual misconduct.'

Decision maker Dawn Dandy acting for the Secretary of State said that Harrison should be banned from teaching for life.

Harrison admitted the offences at Ipswich Crown Court in September 2011 and the judge detained her in a psychiatric hospital.

The court was told the teacher swapped numbers with her victim at the girl's 15th birthday party.

And the judge was told that during a walk in the park Harrison told the teenager 'don't tell anybody about this.'