“The deprivation of liberty of Jordi Cuixart, Jordi Sanchez and Oriol Junqueras is arbitrary,” they write in the Spanish version of a preliminary version of the report seen by AFP on Wednesday.
The final report by independent experts commissioned by the UN Human Rights Council but who don't speak in the name of the United Nations, is due to be unveiled later Wednesday.
The working group estimates the detention of the three men, which has lasted over a year and a half, goes against the Universal Declaration of Human Rights and the UN's International Covenant on Civil and Political Rights.
Calling for their release and compensation, it only focuses on them and not the six others who are also in jail as they too are tried by the Supreme Court in Madrid.
That's because the three men's lawyer took the case to the UN. Sanchez and Cuixart, respectively ex-president and current leader of separatist civic groups ANC and Omnium Cultural, were jailed in October 2017 as the secession bid was underway.
Speaking from prison, Òmnium Cultural’s president, Jordi Cuixart, said “By calling for an end to our arbitrary detention the UN’s WGAD is denouncing Spain’s violations of our fundamental rights. It is an international disgrace.”
Junqueras, Catalonia's former vice-president, was detained in November. The three are being tried for their role in the organisation of a secession referendum on October 1, 2017 despite a court ban, and a subsequent short-lived declaration of independence.
Like the other six who are in jail, they are accused of rebellion, a controversial offence defined as “rising up in a violent and public manner.”
That is rejected by their supporters and some legal experts who say there was no violence during the secession bid.
The working group points to the “non-existence of elements of violence and the absence of convincing information on facts attributable” to the three.
That “generated conviction among the working group that the criminal accusations against them aim to constrain them due to their political opinions.”
The experts also say that holding a referendum “is allowed in Spain for a large range of themes including the present case.”
Spain's judiciary denies this however.
Referendums may be allowed under the Spanish constitution, but this also pledges the “unbreakable unity” of Spain.
As such, the constitution would need to be reformed before any independence referendum were allowed.