A spike in Suffolk school pupil exclusions in March has raised concerns that children likely to get lower grades may be removed from mainstream schools before they sit GCSE exams.

Figures unveiled under Freedom of Information laws showed that in March this year there were 43 referrals from mainstream schools for Pupil Referral Units (PRUs) – schools which specifically cater for children who are sick, excluded or unable to attend mainstream schools.

An average of all the other months excluding March showed around six per month in Suffolk.

Suffolk Labour education spokesman Jack Abbott said he was concerned that it could indicate attempts to remove children likely to get lower grades before they sit their GCSE exams, and thereby not bring down a school's set of GCSE results – a process known as off-rolling.

'These figures show a very worrying pattern. I don't think that it is a coincidence that the numbers of children with a referral for exclusion spikes just before their GCSEs,' he said.

'Off-rolling is a serious issue and, whilst I hope that no school in Suffolk would knowingly undertake this practice, the county council needs to look into whether this is occurring as a matter of urgency.'

Off-rolling pupils without reason is considered unlawful, the Department for Education said, and confirmed a national review in exclusions was under way.

A DfE spokeswoman added: 'Any decision to exclude should be lawful, reasonable and fair. While exclusion can be used by schools as a last resort to deal with poor behaviour, it should not be used for anything else.

'We have announced an externally led review of exclusions practice to look at how schools use exclusion and in particular why some groups of children are more likely to be excluded than others.'

Suffolk's cabinet member for education Gordon Jones said he was not aware of the figures – but would be asking officials to look at them.

He said he could not guarantee that no school had ever been involved in 'off-rolling' but was not aware of any recent increase.

He added: 'In many occasions removing a child temporarily from a mainstream school to give them more intensive one-to-one teaching is exactly the right thing to for that child and enables them to return to school better able to cope.'