Estelle Morris is calling for new measures to deal with bullying and raise the status of classroom assistants.

The education secretary will announce on Wednesday that bullies who are expelled from school will not be allowed to return and appeal boards are to be asked not to overturn the decisions of headteachers.

The new policy marks a change from that promoted by David Blunkett, the previous education secretary. Blunkett felt that too many pupils were being excluded and urged schools to use expulsion only as a last resort.

Estelle Morris, Blunkett's successor, is believed to have been persuaded by letters from teachers and the parents of bullied children who complained that the current guidelines, which in many cases allow bullies to return after a suspension, fail to act as sufficient deterrent. And Cherie Blair recently gave her backing to a high profile Childline conference on bullying.

Pupils taking weapons to school will also be expelled for a first offence.

Morris will also call for greater respect for classroom assistants and stress that the job needs suitably trained people.

The former PE teacher will also seek to head off the fears of teaching unions by saying classroom assistants will not cover for absent teachers.