Head teachers are reluctant to permanently exclude badly behaving pupils in England, according to the Conservatives. But the government says schools are using more short suspensions as a way of clamping down on misbehaviour.
So what are the best ways of tackling disruptive students?
NICK GIBB, SHADOW SCHOOLS MINISTER
This isn't a helpful way of helping children who do have behavioural problems because if they do sit at home or walk the streets for four or five days and then return to school they have not had the specialist help to deal with their behavioural problems and then just return to school and continue their poor behaviour. Then a few weeks later they are suspended again.
There are a lot of disincentives imposed on head teachers to exclude permanently. For example, heads often face an independent appeals panel where parents appeal against the permanent exclusion of their child. And many of those appeals are held in favour of the parent and the disruptive child then returns to the school...
Headteachers are professionals, they have the best interests of their students at heart. They don't want to have a trigger-happy approach to expulsions - they just need that as the ultimate deterrent which helps them have the authority within the school to impose lesser sanctions on children and to make those effective and credible.
TREVOR AVERRE-BEESON, EDUCATION CONSULTANT
Trevor Averre-Beeson works for private US education company Edison, which has stopped excluding pupils from a school it runs in north London.
The main problem with the whole argument is thinking of exclusions as being some kind of effective sanction when, in fact, they really aren't. Exclusions create problems for schools and create problems for students and parents.
You have [to have] very clear, firm sanctions that work within the school.
Schools have exclusion rooms, or isolation units, within schools for serious incidents. It's far better that a student, let's say, who's been in a fight, is sent to exclusion in school for the day - where he's monitored, and taught by teachers, works on school work, misses his breaks and lunchtimes - than being simply sent home, being on the street, being at home and causing difficulty for parents and the community.
JOHN DUNFORD, GENERAL SECRETARY OF THE ASSOCIATION OF SCHOOL AND COLLEGE LEADERS
[The fall in expulsions] is a result of schools doing managed moves, that's to say schools agreeing that it would better for a pupil to move school at a particular point rather than be permanently excluded.
There was a period where the government was certainly trying to get headteachers to reduce the permanent exclusion numbers. In the last two years, however, we have had a lot more support from the government that there are circumstances in which we need to exclude pupils permanently and people are not being criticised in the same way for doing that.
We have to face the moral dilemma here that headteachers face between the detrimental impact that occurs to the education of others if a disruptive child is kept in the school as against the damage that can be done to that child by being permanently excluded and then not immediately getting the support they need.
Interviews from BBC Radio 4's Today programme.