A CONTROVERSIAL law designed to stamp out sectarian abuse at football matches is coming under legal scrutiny over whether it led to the contravention of two convicted fans' human rights.

William Donnelly and Martin Walsh were convicted of charges surrounding the singing of a pro-IRA song at a match between Hibs and Celtic at Easter Road on 19 October 2013.

Lord Carloway, the Lord Justice Clerk, in delivering an appeal court opinion refused their lawyers leave to appeal over the lack of evidence to conclude there was a likelihood that the Roll of Honour song being sung could incite public order.

But leave to appeal was granted over the conviction under section one of the Offensive Behaviour at Football and Threatening Communications (Scotland) Act 2012 on the question of whether there was a conflict with Article seven of the European Convention on Human Rights.

The leave to appeal involved whether there was, "in the circumstances of the case, a breach in the applicants' right to know, with sufficient clarity, of the nature of the crime, in terms of Article seven".

Today's (thur) appeal is expected to hear arguments for Donnelly and Walsh, thought to be Celtic fans, that the legisltation is not clear over which songs are considered unacceptable.

The pair's lawyers will specifically argue that the Act does not make it clear that singing the Roll of Honour song would contravene the act, arguing also that that there is nothing in the content that expresses words of hatred.

If successful it might have implications for the legislation, sources close to the case said.

Lord Carloway said the appeal would proceed only on the the Article Seven question and added: "That may involve, in due course, a consideration of whether the result of the answer... is that the conviction must be quashed."

A month before the match, a Celtic supporter was convicted after singing the song at a match against Dundee United. He was banned from attending football matches for three years and fined £600.

But five months earlier, a Celtic fan caught singing the song was cleared at Dundee Sheriff Court of inciting public disorder during Dundee's Boxing Day match against Celtic. Sheriff Richard Davidson said during the case the law had been badly drafted.

In February, last year, the song reached the UK Top 40 Singles chart. The band, the Irish Brigade, were asked by supporters group Fans Against Criminalisation to cover the song to highlight their opposition to the offensive behaviour Act.

The Scottish Human Rights Commission has previously raised the "potential lack of legal certainty" over the Act as required by Articles six and seven of the ECHR during the legislation's formation.

It highlighted European Court of Human Right cases which found: "An offence must be clearly defined in law. This condition is satisfied where the individual can know from the wording of the relevant provision and, if need be, with the assistance of the court's interpretation of it, what acts and omissions will make him liable."

SHRC also stressed the fundamental importance of the right to freedom of expression and the role of Parliament in ensuring that the restrictions on this right contained in the Bill met the tests of legality, legitimate aim and proportionality.

Almost half of all people taken to court last year under the laws designed to stamp out sectarian abuse at football matches were acquitted, figures show.

There was action taken against 161 people in 2013/14 with not guilty outcomes in 74 cases (48 per cent).

The Scottish Government pushed through the Act in a bid to get tough on sectarianism in the aftermath of the Old Firm 'shame game' in 2011.

The legislation gives police and prosecutors new powers to tackle sectarian songs and abuse at and around football matches, as well as threats posted on the internet or through the mail.

It created two distinct offences, punishable through a range of penalties up to a maximum five years in prison and an unlimited fine.

But many football fans believe it has needlessly criminalised supporters and that the police already had plenty of powers under existing laws to deal with any issues arising at a football match.

Celtic, which has opposed the initial legislation as the law only applies to football fans rather than the whole of society, last year called for a review of the Act labelling the legislation "unhelpful and counter-productive".

Meanwhile, Holyrood politicians have supported amendments to the Community Empoerment Bill by a Green MSP, which would give fans the right to buy their football clubs.

Celtic said the legislation led to "a sense of discrimination across Scottish football and has brought the law into disrepute when tested in the criminal courts".

Holyrood introduced the legislation in January 2012 and promised a re-examination after two full football seasons of operation and to report back to Parliament one year later.

The deadline for the government review is in August 2015 when Stirling University researchers were due to publish their findings into how the law is operating.

In November, last year the SNP government saw off a call to repeal the Act, insisting the legislation was working. A Labour motion calling for the "flawed" legislation to be scrapped was defeated by 68 votes to 50 after a debate in the Scottish Parliament.