Notorious paramilitary killer Michael Stone has been released from prison.

The decision was taken by parole commissioners on Monday and Stone was freed from Maghaberry Prison on Tuesday, the PA news agency understands.

Stone, a former member of the Ulster Defence Association (UDA), killed three people in a gun and grenade attack at Milltown Cemetery in west Belfast following an IRA funeral.

A legal challenge had been launched by his victims’ families in a bid to prevent him applying for early release from prison, but was dismissed by the Court of Appeal last year.

He was freed under the Good Friday Agreement in 2000 but was returned to prison six years later for trying to kill then Sinn Fein leaders Gerry Adams and Martin McGuinness at Stormont.

In November last year, Northern Ireland’s highest court ruled that Stone could apply for early release from prison.

It said keeping the notorious paramilitary behind bars until at least 2024 would “constitute an interference with the physical liberty of the prisoner and could only arise under clear authority of the law”, and in its view this could not be implied.

The issue under consideration was whether he would stay in jail until at least 2024, or whether his minimum tariff expired in 2018, including the six years he was freed under licence.

The court concluded that the period that the prisoner spent lawfully on licence ought to be included in the relevant part of his sentence.

Stone had been serving a 30-year jail term.

One of his victims was 20-year-old Thomas McErlean.

His sister, Deborah McGuinness, had taken legal action in a bid to attempt her brother’s killer from applying for early release.

Stone killed three people in a gun and grenade attack at Milltown Cemetery in west Belfast following an IRA funeral.

He was freed under the Good Friday Agreement in 2000, but was returned to prison six years later for trying to kill then Mr Adams and Mr McGuinness at Stormont.

Last year Stone was ordered by the High Court in Belfast to serve a further five and a half years before he can be considered for release.

An appeal against that ruling was taken to the Supreme Court.

Stone was found guilty of three other killings in addition to the Milltown Cemetery attack that took place on March 16 1988.

They included murdering a milkman, shooting a joiner in the head and firing at another man up to 16 times with a submachine gun.