Even before the murder of Sarah Payne, the government was coming under pressure to do more to protect children from known sex offenders.

In response to public anxiety, a series of measures has been introduced to monitor potentially dangerous men in the community, and other changes are expected to follow as part of a review of current laws.

The Act has significantly moved forward the monitoring of sex offenders. Over 97 per cent of those required to register have done so

Home Office

The Home Secretary, David Blunkett, acknowledges that sexual crimes cause great concern among the public.

"When children are the victims, the sense of outrage is particularly strong," he says.

"We are determined to take every opportunity of building on and strengthening the steps already taken to protect the public from these offenders."

Monitoring

When the Sex Offenders Act came into force in 1997, it created a register of sexual offenders, giving the police the power to monitor paedophiles.

Time for Sarah's Law?

Roy Whiting was one of the first men to have his name placed on the register in June 1995 after being found guilty of kidnapping and indecently assaulting a girl, aged nine.

All offenders convicted of serious sexual offences must now keep the police informed about where they are living, and any change of address.

The length of time a person's details are kept on file is determined by their sentence. Anyone jailed for 30 months or more for a sexual offence will remain on the register for the rest of their life.

The penalty for failing to comply can be a heavy fine or a prison sentence of up to five years. So far, more than 97% of offenders required to register have done so.

The names of sexual offenders are "flagged" in the Police National Computer. This does not offer enough scope for analysing the data, and the Home Office accepts there is a need for an improved computerised system of registration.

Adequate protection?

By March 2001, the number of people on the register had reached 15,000, with another 2,000 being added every six months.

Nearly two-thirds of the offenders have committed crimes that require them to be registered for life, so the numbers are bound to increase.

Sex Offenders

15,000 sex offenders on register Nearly two-thirds are registered for life Up to five years in jail for failing to register 97% have complied

The Home Office says that the register of sex offenders is only one of a range of measures designed to protect the public.

The Early Warning System, introduced in 1999, is used to alert agencies to the release of potentially violent offenders and those convicted of sexual offences.

Risk assessment, prior to their release from prison, or discharge from hospital, is intended to ensure they do not pose a risk once they are back in the community.

Courts can impose a Sex Offender Order to place restrictions on the movements of an offender considered to pose a threat to the public.

Sex offenders can be ordered to stay away from schools, parks, playgrounds, and other places where children gather. Although the legislation is part of the civil law, breaking an order is a criminal offence.

Limitations

Legislation also exists to prevent those convicted of crimes against children from taking jobs that would involve working with youngsters.

Roy Whiting was one of the first on the register

But questions have been raised about whether some police forces do little more than collect the names of sex offenders.

Officers in the Sarah Payne case say limitations on manpower and resources make it difficult to keep track of the increasing number of offenders on the register.

And a recent Home Office report warned there was a danger the register could create unrealistic expectations on the part of the public.

The debate about how much people should be told about sex offenders living in their neighbourhood intensified after the murder of Sarah Payne.

There was controversy when the News of the World decided to "name and shame" paedophiles. The campaign was halted after protests from the police and probation officers.

But demands for the introduction of a "Sarah's Law" have continued, with the schoolgirl's parents receiving strong public support for their demand for greater access to information about sex offenders.

Vigilantes

But the Home Office appears to have firmly ruled out wider access to the register by parents.

A consultation paper on proposed changes in the law says:

Sarah Payne's parents are demanding information about paedophiles

"The government actively considered the matter and took advice from the agencies most closely involved in protecting the public from sex offenders, namely the police and probation services, and from children's charities.

"The government concluded that granting such access was likely to hinder rather than help measures to protect children."

Ministers remain convinced that allowing parents direct access to the register could encourage vigilante attacks and drive offenders underground, perhaps putting children at greater risk.

A review of the system for registering sex offenders is under way, and the government says it is committed to increasing protection for the public, particularly children.

But cases like the abduction and murder of Sarah Payne inevitably create a demand for more stringent monitoring of men known to pose a threat to children.

Chemical castration

One possibility would be greater use of electronic tagging to check on the movements of sex offenders in the community.

David Blunkett recognises "sense of outrage" over paedophiles

This kind of monitoring is already widely used to enforce curfews, and it has proved effective in keeping young offenders off the streets at night.

Now satellite technology developed in the United States offers the possibility of tracking a convicted paedophile wherever he goes.

Such a tag could be set to trigger an alarm if the offender strayed into certain areas, for example, near a school playground or a public park.

In America, some states have passed laws allowing convicted sex offenders to be "chemically castrated" in an effort to stop them re-offending.

As part of the parole process, they are injected with a drug that reduces their sex drive.

Would these kind of measures be regarded as a threat to civil liberties in Britain?

Or would they be seen as a justifiable safeguard as we try to protect our children from predators like Roy Whiting?