Pupils who have been excluded from school are more likely to drink, take and deal drugs and commit crime than their classmates.

They are also more likely to be crime victims, according to a study by Portsmouth University’s social services research and information unit.

The research - funded by the Safer Cities initiative - is based on questionnaires completed by 171 youngsters from a deprived part of a south-coast city.

It says reducing school exclusions is a crucial part of crime prevention.

The report warns: “The narrow drive towards improving academic standards in schools is by-passing the young people most in need of an inclusive education system and putting some of them at risk of involvement, or increased involvement in criminal and delinquent activities.

“It is clearly in the interests of the wider community to ensure that we find ways of including disaffected, often anti-social, sometimes vulnerable and potentially criminal young people (particularly young men) in the education system and through this help forge positive connections with wider society.”

One in five of the respondents - average age 13 - said they had been permanently or temporarily excluded from school, 16 per cent were from ethnic-minority communities, and 55 per cent were boys.

The questionnaire asked if pupils had been involved in committing crime or causing a nuisance. Listed offences ranged from creating graffiti to assault. The 26 excluded pupils had committed at least one offence, and the permanently excluded had offended most.

Misdemeanors included physical assault (72 per cent), truanting (69 per cent), and property crimes (64 per cent shoplifting and 58 per cent damaging property). Nearly a third (32 per cent) of excluded youngsters reported selling illegal drugs.

They were also more likely to have had property damaged or stolen, and to have been assaulted by strangers. The same proportion of non-excluded youngsters reported assaults (50 per cent), but were mainly victims of other pupils.

Dr Carol Hayden, co-author of Safer Cities and Exclusion from School, said there was a clear link between excluded children and criminal and anti-social behaviour. She added that further research was necessary to establish whether exclusion increases such behaviour, or merely confirms existing behaviour.

She is now discussing a project with Hampshire police which would involve checking if defendants in youth courts had been excluded from school.