The primary purpose of the Parole Board is to decide whether the public would be safe if a prisoner were to be released.

It also has a responsibility for ensuring the offender is successfully integrated into society, under the supervision of the Probation Service.

In the case of Robert Thompson and Jon Venables, preparations for the full parole hearings were underway for about six months before the hearings took place.

Much written evidence will have been produced by psychiatrists, probation officers, and staff at the local authority-run secure units where the two offenders have been held.

This will have included information about their response to treatment, rehabilitation programmes and education, and arrangements for their release.

Oral evidence

All of this will have been considered at the full parole hearings, along with representations from the family of the murdered toddler, James Bulger.

The panel, which comprised a judge, a psychiatrist and one other Parole board member may have taken oral evidence and questioned the offenders.

Thompson and Venables' cases have been dealt with totally separately.

It does not follow that the decision of the board in one case will be adhered to in the other.

The decisions had to be made within seven days of the end of each hearing.

'On licence'

The decision of the Parole Board in cases such as Thompson and Venables - where the offenders were juveniles when they committed murder - is final.

Only where the murderers were adults at the time of the crime does the Home Secretary have the final say.

Convicted murderers are only ever released "on licence".

This means they can be recalled and imprisoned at any stage throughout the rest of their life if their behaviour gives the authorities cause for concern.