(Bloomberg) -- Stanley Johnson, the father of the UK’s outgoing prime minister, has left China after being caught in a Covid lockdown that spoiled his plans to shoot a travel film in Xinjiang, where London has accused Beijing of widespread rights abuses.

The former Conservative member of the European Parliament, who has pushed for closer ties between the UK and China, was in quarantine in the megacity of Chengdu when it went into lockdown last week. His youngest child, Max, who studied for an MBA at Beijing’s prestigious Tsinghua University and had been due to accompany his father to Xinjiang, told Bloomberg News that Johnson had “left for the UK.”

“We will make a return trip next year when Covid rules are hopefully relaxed,” Max Johnson said in a text message. 

Boris Johnson, who leaves office this week, detailed his father’s experience in hotel quarantine, a requirement for all inbound travelers to China, in a letter published in the Sunday Express newspaper. 

“He has been shut in his hotel room for nine days, with food left outside his room by staff in hazmat suits,” he wrote on Sunday, adding that the 82-year-old was told of the lockdown “just as he thought he was coming to the end of his Covid quarantine.”

“When he looks out at the streets of Chengdu, they seem deserted,” he added, describing the city of 21 million people.

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Chengdu’s authorities have given no timeframe for lifting restrictions, raising fears of a reprise of the grueling two-month lockdown in Shanghai earlier this year. Under President Xi Jinping’s strict virus strategy, even a handful of cases can prompt authorities to seal off cities, send the infected to centralized quarantine and enforce mass Covid tests in order to eliminate community transmission.

Earlier this year, Johnson told the South China Morning Post that he planned to spend six weeks from August filming a documentary in the Xinjiang region. The film would retrace 13th-century Italian explorer Marco Polo’s journey along the Silk Road, and be filmed in part with state broadcaster CCTV. 

Read more: UN Report Accuses China of ‘Serious’ Rights Abuses in Xinjiang

Beijing committed “serious human rights abuses” against the Muslim majority Uyghur ethnic group in Xinjiang, then UN High Commissioner for Human Rights Michelle Bachelet said last week. Her long-awaited assessment found “patterns of torture or other forms of cruel, inhuman or degrading treatment or punishment” as part of a campaign that Beijing has defended as an effort to fight extremism.

The elder Johnson told the Post in June that his trip wasn’t “a political exercise” and the Chinese government had been “tremendously helpful,” commenting on preparations for the film.

Once a self-declared “Sinophile,” Boris Johnson became increasingly tough on China during his time in office under pressure from members of his ruling Tory party. 

The UK sanctioned Chinese officials and imposed a diplomatic boycott of the Beijing Olympics over alleged rights abuses in Xinjiang and banned Huawei Technologies from Britain’s 5G network due to security concerns. He also opened a visa program for Hong Kongers wanting to escape the former British colony after Beijing imposed a national security law that curtailed democratic freedoms.

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His father, by comparison, has called for stronger ties with Beijing. In June, he thanked China’s ambassador to the UK, Zheng Zeguang, for assisting with his trip to Xinjiang. Getting access to the remote region is notoriously hard for foreign observers, who are typically tailed by government officials. Zheng was banned from the UK’s parliament after China sanctioned British politicians.

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