Magee walked free from the Maze prison after serving 14 years for planting the bomb aimed at Margaret Thatcher and her cabinet that killed five people in Brighton's Grand Hotel during the 1984 Conservative party conference.
He was given eight life sentences. The judge told him: "You intended to wipe out a large part of the Government and very nearly did."
Magee was held in English prisons for nine years before transfer to the Maze in 1994. He is the 277th prisoner to be freed under the early release provisions of the Good Friday agreement, which have benefited republican and loyalist groups who maintain ceasefires.
David Trimble, Northern Ireland First Minister-designate, contrasted the release with the IRA's refusal to de-commission weaponry.
He said: "The release will bring home to people the fact that the prisoner releases are continuing even though other aspects of the Agreement, such as disarmament by paramilitary organisations, have not actually moved forward."
Other critics went much further. The former home secretary Michael Howard said: "His release is a disgrace. I have grave reservations about the release of any prisoners before they have served their sentence. I recognise that it is possible to argue that the release of terrorist prisoners was an integral part of the Good Friday Agreement which is designed to bring peace to Ireland.
"Perhaps if this agreement was being observed on all sides there would be a case for the release of Magee, however sickmaking that would be."
He wants releases halted until weapons are surrendered.
The Democratic Unionist party security spokesman Ian Paisley Junior said the release of Magee was "a slap in the face for the democratic process".
He added: "Tony Blair threatens to close down democratic accountability on 30 June yet he says nothing about the release of multiple killers. The Government is acting in the most reckless fashion with the future of Northern Ireland."
The release was also condemned by Donald Maclean, the former Tory Scottish area chairman whose wife Muriel was fatally injured in the bombing. Mr Maclean said: "I think it is totally wrong.
"I think it is undermining the strength of the law. If a case goes through the court, a sentence is handed down by the judge, I think that should stand. I see no advantage in shortening the time, I see no concessions coming from the other side, no benefits to the peace process from it."
The manager of the Grand Hotel caused some surprise when he was reported as saying that Patrick Magee could again stay at the hotel, a decade and a half after he checked into the establishment with a bomb.
Richard Baker who ran the hotel at the time of the attack, said: "As long as he didn't make himself objectionable to other guests or staff, people like himself are always welcome." Patrick Magee is considered unlikely to take up the offer.Reuse content