The announcement came as the station unveiled a package of measures aimed at restoring viewer confidence in its daily prize competitions. Mr Corley will leave as soon as the new initiatives, which include offering refunds to entrants who were wrongly excluded, and a £250,000 charitable donation, have been implemented, GMTV said.

Mr Corley said the station apologised "unreservedly" for the errors, and hoped his resignation, along with the new measures, would help "restore trust" in GMTV.

He said: "We know that competitions are popular with our viewers and GMTV hopes to bring them back when the right controls are in place. These measures are intended to show viewers that the company will have the right systems and compliance procedures in the future to ensure that this will not happen again.

"It is important that people take responsibility when mistakes are made that threaten the trust of our viewers. I hope that my resignation, and the strong measures we have put in place, will help to restore that trust in GMTV."

Mr Corley said a database of possible affected entrants had now been compiled. Anyone who believes they may have been affected can contact GMTV free of charge on the internet or phone to apply for a refund.

The package of measures announced will see 250 free prize draws held at the end of August for affected entrants, each with a £10,000 prize, as well as refunds. A £250,000 donation will be made to children's charity Childline.

Opera Telecom, GMTV's former service provider, will be contributing towards the costs of remedies, the station said.

GMTV also announced a number of new strict measures for the management of future premium rate "interactivity", including the appointment of a compliance officer who will have specific responsibility for ensuring the processes for premium rate service are followed correctly, both internally and externally.

There will also be regular inspections of any outside companies and no premium rate competition will conclude within the same daily programme. All competition finalists and winners will be randomly selected by GMTV employees in GMTV offices.