The team from Birmingham University’s school of education began the two-year study with 193 excluded youngsters, but could not find 52 of the teenagers at the end.

Harry Daniels, one of the report’s authors, said the teenagers who could not be traced were disproportionately female or black.

He said: “I think we did well to keep in contact with the number we did.

This illustrates the difficulty local authorities can have supporting excluded pupils. Many young people changed address and we had to visit them in the kinds of inner-city areas which are treated with trepidation by welfare services.”

The study found that approximately half the teenagers who were tracked were in education, training or employment, two years after their permanent exclusions.

Contrary to expectations, those who were excluded for actual or threatened assault were more likely to have an occupation than those excluded for verbal defiance.

Half the teenagers, who lived in 10 different authorities, said their exclusion had been a damaging experience. But 19 per cent saw it as a positive event which allowed them to escape from an unhappy situation.

Relationships between the young people and teachers in their new schools were better than at their old schools.

The study follows research by the Office for Standards in Education which estimates that around 10,000 pupils are missing from school rolls, many after being excluded.

The Government’s children’s and young persons’ unit is funding councils to identify pupils who have been lost from the education system and to explore ways of preventing them from disappearing from the records.

The DfES is also considering a national register of pupils whose names are not on school rolls.

“Study of young people permanently excluded from school” is at www.dfes.gov.ukresearch