The government's determination to cut school exclusions is driving teachers towards industrial action, a teaching union has warned.

The National Association of Schoolmasters Union of Women Teachers (NASUWT) has revealed that ballots are already underway in seven schools where its members are threatening to take action rather than teach violent or disruptive pupils.

General Secretary Nigel de Gruchy said new rules making it harder for schools to exclude pupils were "wreaking havoc" with school discipline.

He said: "This union will not stand idly by while its members have to pick up the pieces of the government's impractical ideologies."

Call for meeting

The NASUWT is joined in its opposition to the government's policies by the Secondary Heads Association (SHA), which says the rules intended to promote social inclusion and cut exclusions make it more difficult to maintain good behaviour in the classroom.

SHA General Secretary John Dunford has called for an urgent meeting with the Education Secretary, David Blunkett, in the New Year, to discuss the operation of government regulations.

The government has set targets to cut the number of children playing truant from school and being excluded by one third by the next general election.

It is also spending �500m over three years on schemes to help schools cope with disruptive children, but the NASWUT and SHA say this is not enough.

SHA says that excluding a disruptive pupil is often the only way to preserve the education of other children, and that in extreme cases, it can be the only way to protect other pupils' safety.

'Last resort'

The guidelines as they stand demand too much bureaucracy and local education authority involvement, and are too prescriptive, it says.

Mr Dunford said: "In recent years, schools have often been blamed for excluding pupils. In fact, head teachers do everything possible to avoid exclusions and use them as a last resort.

"When a pupil is excluded, the head teacher is acting as the guardian of the interests of the other pupils in the class.

"Exclusion can be an expression of a head teacher's determination to uphold standards in the school. Used sparingly, it can represent a positive statement about the ethos of the school."

Education Minister Estelle Morris said nothing in government guidance prevented a head excluding a pupil who was a serious risk to others.

The guidelines said governing bodies should consider a wide range of matters before confirming an exclusion, including whether a head had tried sufficient alternative strategies to improve a pupil's behaviour.

She said: "The number of exclusions from schools is unacceptably high. Many excluded pupils never re-integrate and risk exclusion from mainstream society later in life.