A children's charity wants a change in the law to protect vulnerable 16 and 17-year-olds from cruelty and sexual exploitation.

A study by The Children’s Society shows 1,422 youngsters across Sussex are at risk.

The Children In Need Census for the Education Department shows that Brighton and Hove has 187 “at risk” children, while West Sussex has 511 and East Sussex 724.

The figure makes up more than 20% of the total of 6,680 16- and 17-year-olds “in need” in the South East in 2013/14.

While large parts of English law treat anyone under 18 as a child, the Children and Young Persons Act 1933 only protects children from ill-treatment until their 16th birthday.

The Children’s Society said police find it harder to prosecute an abusive parent of a child aged 16 or 17.

The charity wants MPs to extend protections against cruelty to cover this age group.

The Serious Crime Bill will be debated in the Commons early in the New Year. The move would involve increasing the age at which a child can be a victim of cruelty from 15 to 17.

Matthew Reed, chief executive of The Children’s Society, said: “It is nonsensical that adults cannot be prosecuted for behaviour against children aged 16 or 17 that would be considered cruelty if the victim was 15.

“If MPs are serious about stopping child cruelty they must close this legal loophole.”

West Sussex County Council said the 16 and 17-year olds identified in the study were still children in need as defined by the Children Act 1989.

A spokeswoman said: “These young people will have come to the attention of our Children Social Care Service for a number of reasons, including having suffered harm in the family.

“They have an allocated social worker, who works with them, their family, kin and community networks to create a safety plan reducing harm.”

An East Sussex County Council spokesman added: “We work closely with the police to ensure children of all ages are kept safe. We wouldn’t stop protecting 16 and 17 year olds just because of their age.”