Three primary schoolchildren under the age of 12 were excluded from school for sexual misconduct last year.

The youngest was aged six and the other two were between 10 and 11 years old.

The children were suspended from school for a short time before being admitted back into classes.

Overall there were 73 permanent exclusions across Croydon’s schools and 1,757 fixed-term exclusions in 2009-10.

Councillor Tim Pollard, cabinet member for schools, said children being expelled for serious incidents was “quite rare” and the council was working to improve behaviour in primary schools.

He said: “The acute cases that have been highlighted of young children being excluded for quite serious offences such as sexual misconduct, drug or alcohol abuse and possession of an offensive weapon are thankfully quite rare.

“These incidents are sometimes symptomatic of quite chaotic families with complex needs, who often require intervention from a number of council services.”

Figures show one child, aged eight, was expelled for drug and alcohol use, 20 students were made to leave school for possessing an offensive weapon, of which nine were permanently excluded.

This saw an increase from last year, where 15 pupils were excluded for the same offence – six permanently.

Croydon’s rate of exclusions is still above the national average, but the council said permanent exclusions were at their lowest in 16 years.

The most common reasons for exclusion was disruptive behaviour and children assaulting other pupils.

The council is setting up an exclusion hotline that teachers can call for emergency advice and support, if they have a student who is on the verge of expulsion.

Coun Pollard said: “The council has a number of ways in which it supports children and families.

“These include the child in need process through social care, parenting support workers in the youth offending services, the family intervention project, the strengthening families strengthening communities programme and the council’s support for a number of voluntary sector community organisations, which provide services to children, young people and families from a variety of communities.”