The government will face criticism over its close relationship with China on Tuesday as a report will highlight the ongoing use of torture, detention of human rights lawyers and repression of the media.
The Darkest Moment will be launched in Parliament by the former Governor of Hong Kong Lord Patten and supported by former Foreign Secretary Sir Malcolm Rifkind. It examines evidence of human rights abuses over the past three years and heard from Joshua Wong, leader of the pro-democracy Umbrella protests in Hong Kong, and Anastasia Lin, the Chinese-born winner of Miss World Canada who was banned from China because of her human rights work.
The report points to "overwhelming evidence of a very grave deterioration" in human rights in China and urges the government to adopt a more "appropriately critical friendship".
It said: "'While we recognise the strategic and economic significance of China, we do not believe that it is in anyone's interests for the United Kingdom Government to be almost silent, publicly, on human rights, in light of such a grave deterioration."
Speaking ahead of the launch, Lord Patten said: "This is a comprehensive and well researched analysis of China's increasingly deplorable human rights record. I am obviously concerned about what has been happening in Hong Kong.
"The British Government must take account of this first class piece of work."
Rifkind said: "I very much endorse this report and its recommendations. It is an excellent, professional and well researched study. Its recommendations are spot on. This report highlights the urgent need for reform in China. It deserves to be read and implemented."
The report will be launched by the Conservative Party Human Rights Commission. Fiona Bruce, chair of the commission, said: "Without exception, every submission to our inquiry detailed a severe deterioration in human rights in China since 2013 and revealed a situation which is the worst China has seen for many years, possibly since the Tiananmen Square massacre of 1989. Witnesses told us that many recent developments were "unprecedented".
"In light of this, we believe it is time for the UK Government to rethink its approach to China, to speak out publicly and consistently on human rights, and consider ways it can more effectively promote and protect basic rights that are being gravely violated in mainland China and in Hong Kong."