Head teachers do not have the power to exclude dangerous and violent pupils from schools. And thousands of children have been allowed to return to the region's classrooms despite being disciplined for offences such as drug dealing and sexual misconduct.

About 50,000 children were suspended from West schools last year. But figures show since the introduction of fixed-period exclusions, previously known as suspensions, fewer than 1,000 have been permanently excluded. The remainder have been allowed to return to school after a temporary absence.

The Conservative party claims thousands of children are being suspended from schools for offences that warrant expulsion.

The latest Government figures, for 2006/07, show there were 53,922 suspensions in the West. Gloucestershire and Somerset had the most with 9,620 and 8,960 respectively. Meanwhile, North Somerset had the lowest number of fixed-period expulsions with 1,880.

The two rural counties also dished out the most permanent exclusions, with 230 each.

Among those disciplinary actions in the West, almost 1,650 were for drug and alcohol related offences, about 400 for racist behaviour and 400 for sexual misconduct. Almost 800 temporary exclusions were for bullying and almost one in three was for persistent disruptive behaviour.

Government figures show there were more than 3,000 permanent exclusions in 2006/07, 990 of which were in the West.

Dorset, Poole and North Somerset had the lowest number of permanent exclusions, with fewer than 30 each.

The Tories claim large numbers of children are being handed what used to be known as suspensions instead of permanent exclusions because the Government has made it harder for head teachers to expel unruly pupils.

Shadow Children's Secretary Michael Gove said: "Head teachers need discretion to choose the appropriate sanction when a child is seriously disruptive or violent.

"But these figures show that teachers have to rely on suspensions because they don't have the necessary powers to exclude.

"Parents and teachers are increasingly concerned at standards of behaviour in the classroom.

"A handful of badly behaved children can ruin the learning environment for everyone in the class. They should be excluded so they can get the specialist help they need in order to return to a mainstream school."

But Behaviour Minister Delyth Morgan attacked the criticism.

He said: "It is complete nonsense to claim teachers don't have the necessary powers to exclude pupils. Head teachers have the clear statutory power to exclude pupils where they believe it to be necessary.

"More schools are using suspensions as a way of clamping down on misbehaviour before it escalates to the point where permanent exclusion is necessary. This suggests that schools are using them as a short sharp shock to tackle disruptive behaviour.

"Our guidance is clear that in exceptional circumstances it is appropriate to permanently exclude a child for a first or one-off offence. Ultimately it's up to teachers to discipline pupils as they see appropriate."

The Tories say there were 207,240 fixed-period exclusions in 2006/07 for offences which could warrant expulsion in England.

These figures relate to the number of suspensions, not the number of children suspended.

The Government statistics show 138,390 children received one suspension in 2006/07.

The number of children suspended from school more than 10 times in a year has more than doubled since 2004, up to 830 from 310.

Official Government guidance on offences meriting expulsion states the decision to exclude a child permanently is a serious one, that will usually be a final step for dealing with disciplinary offences.

But it adds there are exceptional circumstances where it may be appropriate to exclude a child for a first, or one-off offence. These might include serious, actual or threatened violence against another pupil or staff member; sexual abuse or assault; supplying illegal drugs or carrying a weapon.

The figures come days after it was revealed police were called into schools to tackle violent incidents more than 7,000 times.

The Tories, who accessed the figures under the Freedom of Information Act, claimed head teachers were being undermined, as their decisions to exclude children were overruled by appeals panels in one in four cases.