Monday 17 October was not only set-up day at Frankfurt Book Fair, it also marked a year to the day that Gui Minhai vanished from his holiday home in Thailand at the hands of unidentified agents. For three months his family went without news of his welfare or whereabouts, before he resurfaced in Mainland Chinese police custody.

Today Gui Minhai is still languishing in solitary confinement in a Ningbo prison, and there is no news of what lies in store for him. His daughter, Angela Gui, who describes herself as an 'accidental activist', attended the IPA Freedom To Publish Committee meeting this week in Frankfurt. She gave a personal account of the deeply troubling case, and provided a valuable update on her unstinting campaign to free her father.

“I have only spoken to him on the phone three times since it happened, and each time I got the sense he was speaking under duress,” she told the committee. The biggest giveaway was his choice of English instead of Swedish.

“He said he was fine, that everything would be okay, and that he didn’t want any kind of consular or legal assistance,” she said. “But he was subdued, and something about the way he was talking told me it was all stage-managed.”

Despite appeals to keep quiet from some quarters, Angela, 22, has mounted a concerted international campaign to shine a spotlight on her father’s plight and press the governments of China and Sweden to end his illegal incarceration.

“I believe making as much noise as possible is the right thing to do. Even if we don’t actually manage to get my dad out, there have been cases where this kind of pressure has pushed governments to improve a prisoner’s living conditions, move them to a better facility, to let them to speak to their families more.”

The other four abducted booksellers, who were all linked to Gui Minhai’s Causeway Books publishing house and bookstore, have now been released, raising fears that China will scapegoat Gui for whatever crimes it claims have been committed.

China has yet to reveal the precise nature of the charges against Gui, although according to official Chinese information, he was wanted over an alleged car crash in which a person died. But Angela says neither she nor anyone else who knows Gui had ever heard of such an incident.

One of the IPA Freedom to Publish Committee’s jobs is to gather information about violations of freedom to publish around the world and determine the IPA’s response. Angela asked the committee to help her keep Gui Minhai high on the wider freedom of expression agenda, to which the members agreed without hesitation. But beyond the immediate concern of her dad’s wellbeing, Angela also pointed out that the once audacious and osé Hong Kong book business has been cowed into silence by the Causeway Books case.

“My dad was one of very few people publishing political books that were critical of the Chinese leadership. Most of the people buying these books, which amounted to gossip really, were from Mainland China, but now there is nothing like that being produced; he was kind of performing an important service. It’s terrible that China has so easily been able to shut that down.”

The IPA will continue to work with Angela and its partners, such as the international PEN network, to publicize and condemn Gui Minhai’s treatment and that of other publishers and writers like him elsewhere in the world.