LONDON — Sergei Loznitsa's Imperium, a documentary assembled from footage that Italian camera crews shot across the Soviet Union in the early 1970s, won the best film award at the 70th BFI London Film Festival on Sunday, hours before the festival closed with the UK premiere of Jesse Eisenberg's The Debut.

The prize caps a strong autumn for the Ukrainian director, whose 175-minute film premiered out of competition at Venice last month, and it confirms London's official competition as a showcase that rewards formally demanding work over star vehicles.

The jury, led by the American documentary maker Sam Pollard, said the film offered a view of a country that has rarely been seen on screen. "The film is richly evocative and emotionally engaging on all levels, giving us a visually arresting perspective of life before the Soviet Union was broken apart," the jury said, according to Variety and The Hollywood Reporter.

Pollard, whose credits include MLK/FBI and Citizen Ashe, sat alongside the Argentine filmmaker Mariano Llinás and Julie La Bassiere, chief strategy officer at the publicity firm DDA, Variety reported.

Imperium contains no narration and no interviews. Its material was filmed between 1970 and 1973 with official Soviet permission, and critics at Venice noted that the Italian crews recorded a diversity of regional life that sat awkwardly with the uniform image the state preferred to project. Screen Daily, which reviewed the film in Venice, described it as a hefty but fascinating watch.

The film was produced by Philippe Bober and Anne-Claire Martin of France's Coproduction Office, Uljana Kim of Lithuania's Studio Uljana Kim and Giovanni Pompili of Italy's Kino Produzioni, according to Screen Daily.

Loznitsa, 62, was born in what is now Belarus and grew up in Kyiv. He has moved between fiction and archive work for two decades, winning the Un Certain Regard directing prize at Cannes for Donbass in 2018 and returning to the Cannes competition last year with Two Prosecutors. His earlier archive features include State Funeral, about the death of Stalin, and The Invasion, about Ukraine under Russian attack. In 2022 the Ukrainian Film Academy expelled him after he opposed a blanket boycott of Russian films.

The Sutherland Award for best first feature went to 9 Temples to Heaven by Sompot Chidgasornpongse, a Thai road movie in which a prophecy prompts an ageing grandmother to take her children and grandchildren on a pilgrimage to nine temples. The film is Thailand's submission for the international feature Oscar and premiered in Directors' Fortnight at Cannes, where it was produced by Kissada Kamyoung and the Palme d'Or winner Apichatpong Weerasethakul.

The first feature jury, chaired by the actor Amir El-Masry, called it "an accomplished first feature paving his own path in the well-established tradition of filmmaking in the Southeast Asian region," and praised a film that was "visually outstanding, spiritual, and meditative." A special mention went to Masc, the debut of the British director Bertil Nilsson, about a young man drifting through temporary jobs in search of somewhere to belong.

In the documentary competition, the Grierson Award went to Concrete Land by the Palestinian-Jordanian director Asmahan Bkerat, which follows several generations of a Bedouin family resisting displacement in Jordan. The jury, headed by Santosh director Sandhya Suri, said: "In a noisy and often polemical world, it was refreshing, humbling and deeply relevant to see the quiet resilience and dignity of this family in the face of the erasure of their culture and traditions."

Theo Rollason's Queer Edward II, built entirely from archive material about the making of Derek Jarman's 1991 film against the backdrop of Britain's anti-gay legislation of the 1980s, received a special mention in the same section.

Rahul Roye's Aman, about a trans man who learns he is pregnant on the eve of his gender-affirming surgery, won the short film award and is streaming free on BFI Player until Oct. 25. Elizabeth Hobbs' Daughters of the Late Colonel took a special mention for its inventive visual style.

This year's festival, which opened on Oct. 7 with Simon Stone's Elsinore, programmed 251 titles from 88 countries, including 169 feature films, up from 166 last year, according to figures the BFI released in September and reported by Screen Daily. Forty-three percent of the programme came from female filmmakers, and the number of feature world premieres rose from seven to nine.

The festival's best film award has in recent years gone to films that later travelled widely on the awards circuit, though the competition remains smaller and less commercially driven than those in Venice, Cannes or Toronto. Last year's audience award for best feature went to Chloé Zhao's Hamnet, with Yemi Bamiro's Black Is Beautiful: The Kwame Brathwaite Story named best British discovery.

Those two audience prizes remain open this year. Voting closes on Wednesday, Oct. 21, and the BFI said the winners will be announced later.