A law requiring a mandatory five-year sentence for some convictions under a section of the Firearms Act has been declared unconstitutional by the Supreme Court.

The judgment was delivered in the case of a man who was jailed for five years in 2017 after an appeal court ruled a suspended sentence imposed by a trial judge was too lenient.

In a unanimous judgment the five-judge Supreme Court found the Oireachtas had "impermissibly crossed the divide" between constitutional separation of powers when it enacted Section 27A (8) of the Firearms Act 1964.

In doing so it sought to decide the minimum sentence to be imposed by the court on some, but not all, persons convicted of listed offences, the court ruled.

On that basis, the court granted a declaration of unconstitutionality to Wayne Ellis, with an address at Landen Road, Ballyfermot. 

He was given a five-year suspended sentence in 2014 for an offence under Section 27A (1) of the Firearms Act 1964 after he pleaded guilty to having a sawn off shotgun at Knocklyon shopping centre on 5 July 2012.

He received a concurrent three-year suspended sentence after also pleading guilty to having a sledgehammer and a plastic bottle containing petrol and socks, contrary to the Criminal Justice (Theft and Fraud Offences) Act 2001, in connection with the same incident at Knocklyon.

He was a drug addict with 26 previous convictions but the Circuit Criminal Court took into account he was successfully addressing his drug problems at a treatment centre and had not come to adverse garda attention in the interim.

The suspension was imposed on the basis of the "last chance" principle.

The DPP successfully appealed the sentences as unduly lenient to the Court of Appeal, which imposed the mandatory minimum five-year sentence.

Ellis had separately brought a civil challenge to the constitutionality of section 27A (8). That section provides for a mandatory minimum five-year sentence for certain persons convicted under section 27.

That sentence applies to any person aged over 18 who is convicted of a second or subsequent offence under section 27, or who is convicted of a first offence under section 27 but has been convicted of an offence under certain other provisions of the Act or under section 12A of the Firearms and Offensive Weapons Act 1990.

After the High Court and Court of Appeal dismissed the claims of unconstitutionality, the Supreme Court agreed to hear a further appeal.

The court agreed Ellis is entitled to a declaration that Section 27A (8) of the 1964 Act, as substituted by section 59 of the Criminal Justice Act 2006, is repugnant to the Constitution. 

Ms Justice Mary Finlay Geoghegan, giving the court's main judgment, stressed the consequences for Ellis' of the declaration was a matter for the Court of Appeal to decide as its decision on Ellis' appeal over the five year sentence was informed by Section 27A (8).

That appeal should be "promptly" re-entered before the appeal court, she said.

Ellis was entitled to the declaration because the Oireachtas, in enacting Section 27A (8) had impermissibly crossed the divide in the constitutional separation of powers and sought to determine the minimum penalty which must be imposed by a court, not on all persons convicted under Section 27A (1) but only a limited group, those who have previously committed one or more of the listed offences, she said.

In a concurring judgment, Mr Justice Charleton agreed the provision should be struck down.

That does not mean, and should not mean in this case, the automatic release of the offender which was a matter for the Court of Appeal.