Headteachers are being frustrated at being overruled as they try to get tough on yobs.

Suspensions from secondary schools for threatening teachers, attacking other pupils or disrupting lessons were up 14,000 last year – four per cent – compared with the previous year. In England, secondary pupils were excluded 343,840 times in 2005/06, according to the Department for Education.

Education minister Jim Knight said this showed schools were getting tough on unruly youngsters.

But Mick Brookes, of the Nat­ional Association of Head Teach­ers, warned that reinstating an expelled pupil can create “havoc”.

It sent a message that disruption was acceptable and led teachers to take action in protest. Mr Brookes said: “The child continues to disrupt the education of others.” He said the pupil put back may think “I can do what I want because you are not allowed to exclude me.”

Almost a quarter of appeals against expulsion were successful and, in these cases, more than half the pupils returned to their school.

John Dunford, of the Association of School and College Leaders, said: “Heads need and deserve better support than this if they are to maintain standards of behaviour.”