Salmond's blustering legal bids aren't going to win him equal time on TV election debates

DOUBTS have been raised over the legality of the TV debates between potential prime ministers which, it is hoped, will enliven the general election campaign. Leaders' debates at election times are nothing new for Scots viewers, who have had the opportunity to watch rival parties since 1992.

What will be new in 2010 is the series of debates between three British political party leaders being broadcast by the BBC, ITV and Sky to viewers across Britain.

The SNP, undeniably a major player in Scottish politics, has been regarded as sufficiently minor in the context of a British general election to justify its omission from the leaders' debates.

Alex Salmond has led a chorus of complaints and threats. Along with the Welsh Nationalists, Plaid Cymru, he has accused broadcasting organisations of partiality and even suggested that there will be a breach of the human rights law requirement of "free elections".

The three broadcasters have been brought to the table and ensured the nationalists will feature prominently in other shows on the election broadcast in Scotland or in Wales. Some of these programmes are likely to be four-way debates. Other formats under consideration include ways of linking an SNP speaker to the leaders' debates by some kind of follow-up.

The broadcasters must show "due impartiality" in their coverage. The obligation is legally enforceable, and the First Minister has reminded some questioners that a Scottish court may intervene to ensure fairness.

No doubt he had in mind 1995's Panorama affair. Then the Court of Session, at the instance of Labour and Liberal Democrat candidates, stopped an interview with Tory Premier John Major being shown in Scotland three days before local elections – the lack of similar opportunities for other parties made it harder for the BBC to demonstrate its impartiality.

Other cases give clear signs that the Scottish courts will distinguish between Scottish and British elections when appropriate. When the SNP litigated over its relative neglect in networked news bulletins like News at Ten, it lost, as it did when complaining of the greater coverage the BBC gave in one year to the other parties' conferences. There was another defeat when it demanded more general election broadcasts.

Most relevantly for the leaders' debate, there was litigation in 1997 when a "head-to-head" between John Major, Tony Blair and Paddy Ashdown was a serious prospect – although ultimately not agreed. STV and Grampian admitted that, if the debate were arranged, there would be no place in it for Alex Salmond, and the SNP took them to court. Lord Eassie dismissed the case as hypothetical. Importantly, he considered the requirement of due impartiality should be viewed holistically rather than be applied to a company's single programmes in isolation.

These judicial views suggest the omission of a small party from any single programme would not be unlawful, and the SNP is a small party in a UK context. In 2005, its share of the votes cast in Scotland was 17.7 per cent, but its share across the UK was 1.5 per cent – lower than UKIP's. Salmond has played a poker hand with bluff and bluster, but it is a weak hand.

• Colin Munro is Emeritus Professor of Constitutional Law at the University of Edinburgh.