A SCOTTISH expert in international law has said the exclusion of defence witnesses at the trial of Catalan independence leaders, which is due to start tomorrow, is a matter of concern under European legislation.

Spain’s Supreme Court rejected attempts by lawyers for the dozen accused – former Catalan government ministers and two grassroots activists – to call three UN special rapporteurs to give evidence.

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However, William Henderson, of Glasgow Caledonian University (GCU), whose research interests include the European Convention on Human Rights (ECHR), said authorities would only likely become involved if the refusal impacted on the fairness of the case.

Speaking exclusive to The National, he said the ECHR and International Covenant on Civil and Political Rights (ICCPR) gave the accused the right to bring witnesses to their own defence, but their scope was limited.

“The internal regime that is in place within a state and the internal domestic rules of evidence are given a particularly heavy weight, especially by the ECHR, so the European court does not become an appellant court in addition to the national legal systems,” he said.

“That gives rise to complications where you’re facing a situation like this, where the Spanish authorities are bringing forth their witnesses and the defence are having witnesses excluded ... only where there’s an overall detrimental impact upon the fairness of the case would the authorities become involved.”

Henderson said the exclusion of the special rapporteurs was particularly serious given the charges – sedition and rebellion – the accused are facing: “When we’re dealing with aspects of minority rights, human rights defenders and issues around freedom of expression and opinion and belief, there’s a very strong argument that the UN special rapporteurs, some of whom have produced reports under the UN human rights system under their special procedures mandates, should be participating as witnesses called by the defence in that trial.

“Institutions at the core of my work are the ECHR and the Human Rights Committee, so their involvement would be triggered by complaints being made to them, but the limits that exist under those systems are again the exhaustion of domestic remedies … that requires having the Spanish state’s judicial process run its course before action then is taken.

“The other ways the world or the international community would become involved in this is through the likes of the UN special procedures and we’ve already seen the special rapporteurs going back to 2017 expressing concerns in relation to the referendum initially and more recently in terms of what’s happening within the process of the trial – not only existing UN special rapporteurs but former special rapporteurs like Ben Emmerson as well.”

READ MORE: Jordi Cuixart: Catalan trials will judge Spanish democracy

Meanwhile, more than 40,000 Spaniards gathered in Madrid yesterday, calling for socialist Prime Minister Pedro Sanchez to resign for holding talks with the Catalan independence lobby.

It was led by conservative opposition Popular Party (PP) and the centre-right Citizens. Far-right Vox also backed the demo. PP president Pablo Casado said: “The time of Mr Sanchez’s government is over.”