A new film about a gossipy and scheming group of cardinals who must select the new Pope has received its UK premiere at the London Film Festival.

Conclave, which stars Ralph Fiennes, Stanley Tucci and Isabella Rossellini, is adapted from the 2016 novel by Robert Harris.

The film is thought to be a strong contender for the best picture award at next year's Oscars, and several of its stars could also be in contention for individual acting prizes.

Conclave is directed by Edward Berger, the acclaimed German-Austrian film-maker whose 2022 adaptation of All Quiet on the Western Front was nominated for nine Academy Awards.

Conclave opens with the death of the Pope, prompting cardinals to gather in Rome to select a new head of the Catholic Church.

But behind the scenes, there is skullduggery, wheeling and dealing, and conspiracy as the frontrunners try to improve their chances.

The reliable and strait-laced Cardinal Lawrence (Fiennes) finds himself tasked with overseeing the selection, a process he gradually wonders if he should enter himself.

In a performance that could make waves during awards season, Fiennes' character goes on manoeuvres as he attempts to shape the outcome of the race.

Berger, Harris and the film's stars attended its London Film Festival premiere on Thursday at the Royal Festival Hall.

Conclave starts slowly - after the Pope dies in the opening scenes, it takes a while to set up the premise of the film and introduce the contenders to replace him.

But, over the course of two hours, the movie becomes more gripping.

"Don’t be fooled by how tedious the premise of finding a new Pope might sound on paper," advised the AV Club's reviewer Tomris Laffly.

"In Berger's studious and elegant hands, every ceremoniously cast vote, every reaction shot, every severely worn regalia and every quietly eventful meal that the cardinals share is packed with breathless, skin-prickling suspense."

Conclave is "a sophisticated and sharply enthralling thriller," wrote Mashable's Kristy Puchko, describing it as "a movie that understands the complications of Catholicism".

"Berger’s film is adapted, quite faithfully, from Robert Harris’s 2016 novel," noted Vulture's Bilge Ebiri, "and it combines the pulp velocity of a great airport read with the gravitas of high drama."

There is one slight contrivance later in the film to set up its final act, but it's arguably a necessary one to set the stage for the film's dramatic conclusion.

"Even viewers who may guess the identity of the next Pope will be surprised by the final twist, which is very much in keeping with the film's ambition to bring the certainties of the past into an unpredictable, dizzying, but essential new future," said the Hollywood Reporter's Steven Farber.

"The twist will be known to those who have already read the book," said Entertainment Weekly's Maureen Lee Lenker. But to anyone else, she said, the ending is "the mark of an impeccably crafted thriller".