One of Italy’s most acclaimed writers is facing up to five years in prison for “incitement” after he called for the sabotage of a controversial high-speed rail line between Italy and France that has become a flashpoint for environmentalists and opponents of globalisation.

The trial against Erri De Luca, which begins on Wednesday in Turin, marks a high-profile development in the 20-year battle over the line, which has faced years of delay because of massive – and sometimes violent – protests.

For supporters of the 64-year-old De Luca, a self-described anarchist who has been hailed as one of the most important writers of his generation, it is also an important test of free speech in Italy.

“There is a new will of censorship,” De Luca said. “I am under trial, but that trial is under the watch of public opinion.”

The case centres on two media interviews the Neapolitan writer and activist gave in September 2013, in which he called the rail line a “useless and harmful project” and said it was “legitimate to sabotage” it.

The rail project, which is known as TAV, has been fiercely opposed by local residents in the Alpine Susa Valley for decades because of fears that its construction will release asbestos and other toxins and contaminate the environment.

But it is not just a local issue. The “No TAV” movement has become a rallying cry for activists across Italy who see the multibillion-euro European project as an encroachment on national sovereignty and a symbol of wasteful and useless exploitation for corporate gain. Many think the project will never be completed, meeting the same fate as hundreds of other public projects in Italy.

Supporters of the 35-mile tunnel, which would connect Turin in Italy with Lyon in France, say it is a key component for a critical rail network that will someday link Lisbon to Kiev, and Rome to London. They say it will boost trade, lower transport costs, and boost commuter rail services, making it possible to travel from Milan to Paris in just four hours rather than the current seven hours.

The French firm building the rail line, Lyon Turin Ferroviaire, pressed charges against De Luca shortly after he made the remarks and Italian anti-terror prosecutors followed suit, claiming that the writer had “publicly instigated the commission of crimes and violations” intended to hurt the French company and the construction site of the TAV, which has been deemed an area of strategic national interest and is now protected by military checkpoints.

A handful of arson attacks along other Italian rail lines late last year have been blamed on ‘No TAV” activists.

Maurizio Bufalini, the managing director of LTF in Italy, said it was easy to demonise his company for trying to silence De Luca, particularly after the public outpouring of support for free speech in the wake of the Charlie Hebdo terror attacks in Paris.

“But it is correct to remember that if someone says something that can have an impact on the life and safety of the people working there, we are obliged to do something,” he said, pointing out that he and other people involved in the TAV live under the protection of armed guards. De Luca, he added, was an important person whose comments could have dangerous consequences.

“Mr De Luca is free to think what he wants and to call for protest -– that is normal -– but sabotage is something else,” Bufalini said.

In a written defence of his actions called A Dissenting Word, De Luca says the word “sabotage” has an “enormous range of figurative uses”, like the word ‘obstruction’.

“I would willingly accept a legal conviction, but not a reduced vocabulary,” he writes. He says prosecutors have not been able to link his words to any specific act of violence.

If he is found guilty, De Luca said he would not appeal against the decision. He faces a possible sentence of one to five years in prison.

Stefano Esposito, a senator from the centre-left Democratic party who supports the rail line, said De Luca was a relic of the ‘years of lead’, the tumultuous political period during the 1970s that were marked by acts of violence and terrorism by left- and rightwing activists. “He is just looking to sell his books,” said Esposito.

But De Luca made light of the criticism. “It’s an incitement to smile,” he said.