The TES last year reported the case of Barry Derriscott, an RE teacher who had a prohibition order imposed for sexually harassing four female colleagues.
He was the first prohibited teacher to successfully register again. Our enquiries revealed that the previous ban would not be disclosed to potential employers.
The GTC's hearing panel had been reassured by Derriscott's "genuine remorse" - but afterwards he told The TES that "90 per cent of the allegations were complete and utter bollocks", his victims were a "coven", and his ban was imposed by a "kangaroo court".
Derriscott, now 37, said he would seek work as a supply teacher.
The headteacher at Pensby High School for Boys on the Wirral had told the original hearing that he would have considerable reservations about letting Derriscott back into a classroom. And headteachers' associations expressed dismay that a banned teacher could be reinstated with no mention of their prohibition on record.
Derriscott would have been identified simply as "registered" if a headteacher phoned the GTC to check his record. Disciplinary records are deleted from the council's website after three months.
By contrast, the General Medical Council has doctors' disciplinary decisions dating back to 2005 posted on its website, and provides a phone line for employers to check back further than that.
This week, the GTC wrote to Derriscott and other teachers with reprimands or suspensions buried on their records, advising them of a policy change.
The GTC's registrar, Alan Meyrick, emphasised that disciplinary orders were already a matter of public record, but from next month they would also be disclosed to potential employers. The policy change aimed to ensure that the GTC's procedures were transparent and maintained public confidence and standards, he said.
The Government tightened up checks on school employees following Sir Michael Bichard's inquiry into the Soham child murders, but Derriscott's prohibition would not show up on a Criminal Records Bureau check because it was not a police matter. He had been struck from the register in February 2005.
In future, the GTC said, a teacher would have to submit three references before their name could again be entered on the teaching register.