IT has been branded a “show trial” of political prisoners which over the past four months has shone a spotlight on Spain’s idea of justice, and this week proceedings against 12 Catalan independence leaders reach their final stages still surrounded by controversy.

Several of the accused have been in so-called “preventative detention” for approaching 20 months, and could face decades in jail if they are found guilty of rebellion and sedition for their part in organising the October 2017 independence referendum in Catalonia.

Five of them were elected to the Spanish Parliament in April’s general election and although they were allowed to take their seats in congress and the senate, they were suspended shortly afterwards.

One of them, leader of the Republican Left of Catalonia (ERC) Oriol Junqueras, also scored a victory in the elections to the European Parliament, but it is not yet known if he will be able to take his seat there. Each accused will have 15 minutes to deliver a personal statement to the Supreme Court. Their lawyers will be given little longer – just an hour – to sum up the defence cases.

Although the trial is scheduled to end this week, the verdicts could take many weeks more.

One of the defence lawyers, Benet Salellas, has warned in the meantime, that Spain could reactivate the European arrest warrants (EAWs) for those former members of the Catalan government – including ex-president Carles Puigdemont and his former education minister Clara Ponsati – who are in exile across Europe. In an interview with public broadcaster Catalonia Radio, Salellas, one of the team defending former president of Omnium Cultural, Jordi Cuixart, held nothing back about the “political trial”, whose verdict could have “extremely dangerous” implications.

“The Supreme Court, before starting the hearing, already had a certain vision of where it wanted to take it,” he said. “This allows us to believe that the judges are acting as executors of a decision that was already taken.

“The trial appears, in its origins, to have been intended to exert influence on the independence process.”

Salellas said he had not given up on stressing the “political dimension of everything that happens in the trial”.

He said: “The legal defence must go hand in hand with a political defence,” adding criticism of the one-hour time limit on summing up: “The court is afraid of granting us time to dedicate to the central issues, and that is a very clear symptom of a political trial. It is extremely unjust.”

Meanwhile, observers who have been monitoring the trial said the public prosecutor’s office had made a political argument, which had taken little notice of basic rights.

International Trial Watch said: “The ... prosecutor’s arguments denote a non-democratic conception regarding the exercise of fundamental rights, such as the right of assembly and demonstration, the right to freedom of expression or the free exercise of public office. It shows the fact that his argument was based on a political argument.”