The abduction of booksellers, the assault on newspaper editors, the imprisonment of pro-democracy activists all show the dangers of challenging Beijing’s line in Hong Kong. It appears that China is now extending its reach further overseas, sending a message that you are not safe outside the country. Hong Kong publisher Gui Minhai was kidnapped in Thailand in 2015, after reportedly preparing a book on the love life of Chinese President Xi Jinping. These letters to UK residents are further proof of the limits some will go to in order to silence those who want to promote autonomy and basic freedoms in Hong Kong.

Evan Fowler is a resident of Hong Kong who is moving to the UK because his life, he says, has become impossible in his home town. We are sitting in a cafe in central London while he recounts intimidation tactics that have been used to try to silence him. It’s a tough conversation.

Fowler wrote for a very popular Cantonese news site, House News, which was forced to close down in 2014. Its main founder was abducted and tortured, and Fowler says he has suffered periods of severe depression since. He, too, recently received letters to his home in Hong Kong, and is aware of several people who have received them in the UK.

“The interesting thing about these letters is that, in my understanding, the letters all contain similar phrases – no direct threats are made, but [there is] an identification of you as an enemy of the Chinese people,” he said.

Fowler speaks of how “the threat level has been increasing in Hong Kong” and says that “Hong Kong pre-2014 is different from Hong Kong after”.

“It’s a city that is being ripped apart,” he said.

Another recipient of the letters, Tom Grundy, is editor-in-chief and co-founder of Hong Kong Free Press, based in the city. His mother, who lives in the UK, also received a letter late last year.

“I am slightly concerned that Tom has taken to a path that has become unsavoury and unhelpful to the some (sic) of the people of Hong Kong,” the letter read. “However, in politics, when one does not know one’s enemies clearly, one could get hurt.”

It added: “I and many people would really regret if something happened to Tom in the next few years.”

When Index spoke to Grundy, he said he was concerned about how they found the addresses of family members, and that the incident had upset his mother.

But, having reported it to the Hong Kong police, he is hopeful that it has been dealt with – the letters stopped immediately upon doing so.

“Journalists aren’t walking around Hong Kong fearing that they are going to be plucked from the streets,” he said.

“Hong Kong has had the promise of press freedom and it’s been a bastion of press freedom for Asia for decades, and NGOs like you and us are concerned and we raise the alarms because we want the civil liberties and freedom to be maintained.”

This does not mean that Grundy doesn’t have his concerns about press freedoms in Hong Kong. It’s just that, for now, the letters aren’t as much of a concern compared with other things happening in the city, such as the as yet unresolved kidnapping of the booksellers, for example.

But for others, these letters have been hard to shake off. Will they have their desired silencing effect? The picture is complicated.

“I think it’s highly unlikely that they would try any physical harm in London, so I don’t feel scared,” said Rogers, adding that it is, however, “not a pleasant feeling”. At the same time, he is keen to stress that he won’t be silenced.

“It’s actually, if anything, made me more determined to carry on doing what I’m doing because I don’t think one should give in to tactics like this.”

His view is echoed by Catherine West, a British MP who is on the board of Hong Kong Watch.

“This sort of intimidation is very unpleasant,” she told Index. West is aware of the two incidences connected to Rogers and encouraged him to go to the UK police.

“Whoever is doing this should realise this will only embolden us to promote human rights,” she added.

Speaking of Hong Kong specifically, West said: “We would like to be sure that freedom of expression is not curtailed and that young people in particular can express it without being curtailed.

“We feel it’s important for parliamentarians around the world to be involved, to be standing in solidarity with one another.”

Jemimah Steinfeld is deputy editor of Index on Censorship