A Vatican court convicted two environmental activists of aggravated damage on Monday and ordered them to pay more than 28,000 euros (£24,000) in restitution after they glued their hands to the base of an ancient statue in the Vatican Museums to draw attention to climate change.

The two members of the Last Generation environmental activist group, Guido Viero and Ester Goffi, also received a nine-month suspended sentence and were fined 1,620 euros (£1,400) each.

A third activist on trial with them, Laura Zorzini, was fined 120 euros (£103).

The trial followed at protest on August 18 in the Vatican Museums, during which Viero and Goffi glued their hands to the base of the Laocoon statue, one of the most important ancient works in the collection, believed to date from the 1st century B.C.

They hung up a banner reading Last Generation: No Gas And No Carbon, as Zorzini filmed them.

Their action was part of a wave of Last Generation and related activist protests around Europe that have targeted museums and other cultural institutions, tied up traffic for days and otherwise caused disruptions in a bid to draw attention to what the activists say is the failure of governments to take action to fight climate change.

In closing arguments, the lawyer for the Vatican City State accused the defendants of exploiting Pope Francis’s known concern for the environmental cause by causing “inestimable” damage to a piece of the world’s artistic and cultural patrimony.

Lawyer Floriana Gigli said Viero and Goffi knew their protest would damage the artwork, citing their decision to glue their hands to the base, not the statue itself, and yet never expressed regret at the damage caused.

None of the defendants was in the Vatican criminal tribunal for the verdicts.

During a hearing on May 24, Viero and Goffi told the court they never intended to damage the statue, but also strongly defended their cause.

Viero told the court he felt an obligation as a father and grandfather to draw attention to Italy’s failure to halt global warming.

Goffi, for her part, recalled she had brought a glue solvent in her bag, but Vatican restorers used a different acetone-based substance to unglue their hands.

Vatican prosecutor Catia Summaria had sought a sentence of two years and a fine of 3,000 euros (£2,600) each for Viero and Goffi and a sentence of one month for Zorzini.

But she said if the court decided on suspended sentences, the defendants should be ordered to repay the full cost of the damage to the statue.

Ms Gigli said the actual cost was impossible to estimate given the statue is a priceless artwork and is permanently damaged.

She asked the court for an appraisal to come up with a figure, saying the restoration work alone had cost 3,148 euros (£2,700).

In the end, the court quantified the restitution owed to the Vatican City State at 28,148 euros (£24,220).

During the previous hearing, the head of the Vatican Museums’ marble restoration laboratory, Guy Devreux, said the damage to the base was ultimately less than he had anticipated but was nevertheless permanent.

He said the marble base of the statute was “absolutely” to be considered an “integral part of the work”.

Last Generation has said it targeted the Laocoon statue, which is believed to have been carved in Rhodes in 40-30 B.C, because of the symbolic story behind it.

According to legend and the Vatican Museums’ own website, Laocoon warned his fellow Trojans against accepting the wooden horse left by the Greeks during the Trojan War.

The group said the climate crisis is a modern-day warning being unheeded by political leaders.