Home Secretary David Blunkett today finally published legislation to lock up Britain's worst paedophiles for life.

The move, which follows a long campaign, was ordered by Mr Blunkett to ensure there are "no more cases" like that of Sarah Payne's killer Roy Whiting, of Littlehampton.

Under the proposals, included in the Government's flagship Criminal Justice Bill, people who commit serious sex offences will be jailed for life - even if it is their first offence.

Whiting kidnapped and murdered eight-year-old Sarah after being released from serving a jail term for a previous sex attack on a nine-year-old girl in the Ifield area of Crawley in 1995.

Under the new rules, he would still have been behind bars when Sarah was snatched from a field in Kingston Gorse, East Preston, on July 1, 2000.

Mr Blunkett warned: "There must be no more cases like that of Roy Whiting, a man sentenced to four years for a terrible kidnap and sexual assault of a child, who went on to commit an even more horrendous crime."

Once the changes take effect, the country's most dangerous paedophiles will face new "indeterminate" life sentences.

That means they will only be released if a parole board decides they are no longer a threat.

Sex offenders who are freed will be closely supervised for up to ten years after they leave jail, double the current period.

They will have to register at a police station every 12 months instead of the current requirement every five years or face up to five years in jail.

The Home Secretary promised reform the reform last December after details of 43-year-old Whiting's conviction emerged.