New orders which come into law on Wednesday allow specific bans to be placed on anyone with a previous conviction or even caution for a sex offence in the UK, or overseas.

Police can apply to magistrates for an order against anyone giving cause for concern - including people who might not be on the 'paedophile register' of known offenders. .

The test is whether the public are at risk from serious harm, which can mean groups of people or even individuals. The risk might come from behaviour which is otherwise quite normal - for instance, parents waiting to collect their own children after lessons.

An aspect of the order is that the person it is used against must register under the Sex Offenders Act.

Offenders who break the orders can face up to five years in prison.

Children's rights

The Home Office Minister Paul Boateng said the orders would give the police a valuable tool to protect children and vulnerable adults from the dangers of paedophiles and serious sexual offenders.

"We are determined to reduce the risk that sex offenders pose to the public," he said.

"The orders will be able to curb the kind of behaviour which may lead to a further criminal offence.

"Our children should be able to walk the streets safely and not feel threatened. They have a right to enjoy their childhood."

The National Association for the Care and Resettlement of Offenders said more treatment programmes for sex offenders and longer periods of supervision after their release from jail would be more effective against offending.

Case example

This is the sort of scenario the Home Office has in mind:

Mr X is cautioned for indecent conduct towards a young child in 1990. Nine years later he begins hanging around outside a primary school at the end of the school day, approaching departing children, offering them sweets and talking to them.

This happens several times and staff and parents at the school are worried enough to report the matter to the police.

The police observe the man, check his previous records and consult other agencies involved with him.

They decide there is no innocent explanation for his behaviour, and there is reasonable cause to believe that if he carries on as he is, there could be serious psychological or possibly physical harm to the young children he appears to be targeting.