Relatives are pressed for large sums of money, forced to falsely claim dead protesters were members of the security forces such as youth militia the Basij, and prevented from holding proper funerals, they charge.
European countries have already ramped up defence budgets since Russia invaded Ukraine, and agreed last year to massively hike NATO's spending target under pressure from Trump.
UK-China relations plummeted in 2020 after Beijing imposed a sweeping national security law on Hong Kong, which severely curtailed freedoms in the former British colony.