The BBC's Chief Security Correspondent, Brian Rowan, explains how plans for the early releases will work.

The Maze Prison, 10 miles from Belfast, holds in its wings most of those convicted in Northern Ireland of terrorist crimes.

Over the next few months, this top security jail with a long history of prisoner protest and confrontation will once again be the focus of media attention.

It was here that Bobby Sands and nine other republicans died on hunger strike in 1981 - a protest designed to win political status for prisoners.

Two years later, the IRA organised a mass escape from the jail and, in late 1997, a prominent loyalist figure, Billy Wright, was shot dead by another inmate.

Under the terms of the Good Friday Agreement republican and loyalist prisoners are to be given early releases.

Four-hundred prisoners affiliated to the Irish Republican Army and to the loyalist paramilitary organisations the Ulster Volunteer Force, the Ulster Freedom Fighters and the Red Hand Commando will benefit from the release scheme.

The dissident republican organisations and the Loyalist Volunteer Force do not qualify for the release scheme.

For those serving fixed terms there'll be an increase in remission from 50% to 66%. That means someone sentenced to 15 years will serve only five.

For prisoners serving life there'll also be a reduction in the average sentence.

All of this is being overseen by a Sentence Review Commission, also established as part of the Agreement.

Prisoners apply to the commission for early release. The commission decides on eligibility and then gives prisoners a "preliminary indication" of its decision.

This can be challenged by either the prisoner or the Northern Ireland Prison Service.

If there is no challenge the commission then issues a "substantive determination".

The distinctive "H" blocks of the Maze

Fifteen preliminary indications were issued last Friday and the first releases are expected later this week.

After two years the release process will be reviewed and all prisoners linked to organisations observing unequivocal ceasefires could be released.

This issue more than any other aspect of the Good Friday Agreement has divided opinion in Northern Ireland.

There are those who can't come to terms with the proposed arrangements and who still argue that those convicted of terrorist crimes should serve their sentences in full.

Those families who have had relatives killed by terrorist organisations will be told when prisoners are being released, but only if they want to know.