Oxfordshire's education director Graham Badman has resigned in the middle of the Oxford schools' reorganisation.

Parents are concerned that Mr Badman, who masterminded the scrapping of the city's middle schools, will not see through the complex changes he recommended.

He will leave in the New Year to take up the post of education director for Kent County Council.

A decision has been taken to switch Oxford from a three-tier education system to a two-tier system by 2003 but many changes are still under way. Campaigners fighting the reorganisation took their case to the High Court but after they lost, they agreed to support teachers and governors to help make the changes.

The resignation of Mr Badman, before the new system is in place, concerned parents, who fear their children's education could be affected.

Annie Skinner, a spokesman for the Save Our Schools group, which fought the shake-up, said: "It is beyond belief that Mr Badman, who so vociferously argued that this plan was in the educational interests of the children of Oxford, could leave the education department now.

"City schools have only just started to adapt to the changes, both in terms of the buildings and in terms of organising staff and pupils. Children deserve to have this reorganisation managed and carried through by the person who initiated the change." The education department was criticised earlier this year for allowing Mr Badman to be seconded to advise London's Hackney Council.

Martin Thomas, the headteacher of Temple Cowley Middle School, which is to close, said Mr Badman's resignation gave the wrong signals.

He said: "The transition period is difficult and this doesn't send out the message to staff that they should be loyal to the pupils and stick around."

Cllr Keith Mitchell, the Conservative leader of the county council, said he regretted Mr Badman's resignation because he was an excellent officer. He said a temporary replacement could be appointed internally until a permanent replacement was found.

In a letter to county councillors, Mr Badman wrote: "I have been very happy in Oxfordshire and shall always regard the county with great affection."

He joined Oxfordshire County Council as chief education officer in 1996. He worked for the county education service in the 1980s, before moving to Avon County Council.