Britain's government on Friday gave its full backing to British lawmakers and others sanctioned by China for speaking out in defence of the Uyghur Muslim minority.
"The MPs and other British citizens sanctioned by China today are performing a vital role shining a light on the gross human rights violations being perpetrated against Uyghur Muslims," Prime Minister Boris Johnson tweeted.
"Freedom to speak out in opposition to abuse is fundamental and I stand firmly with them."
China announced sanctions against nine UK individuals and four entities, saying they had "maliciously spread lies and disinformation" over Beijing's treatment of Uyghurs.
Foreign Secretary Dominic Raab said China's ambassador to London would be summoned to state the government's stance.
"We will explain in very clear terms the position both in relation to the MPs and the other figures who have spoken out, but also that we will not be silenced in speaking out about these human rights abuses," he added.
Raab called on Beijing to give the United Nations full access to the region of Xinjiang if it wants to "credibly rebut claims of human rights abuses".
The sanctions would not stop the government or the individuals targeted from "speaking up about the industrial scale human rights abuses that's taking place in Xinjiang", he added.
He warned "international pressure will continue to grow" as long as China resisted UN access to the region.
China's last ambassador to London Liu Xiaoming left his post at the end of January after 11 years in the position. His replacement, Zheng Zeguang, is yet to be installed and is currently Beijing's vice-minister of foreign affairs.
Justice minister Robert Buckland said "we strongly deprecate" Beijing's announcement, which also targeted a British law firm that has taken up Uyghur rights causes.
Those sanctioned include Iain Duncan Smith, former leader of Britain's ruling Conservative party, along with four groups that have been vocal in driving rights in Xinjiang and Hong Kong higher up Westminster's agenda.
Duncan Smith said it was "our duty to call out the Chinese government's human rights abuses in Hong Kong and their genocide of the Uyghur people".
"Those of us who live free lives under the rule of law must speak for those who have no voice. If that brings the anger of China down upon me then I shall wear that as a badge of honour."
The EU, UK, Canada and US sanctioned several members of Xinjiang's political and economic hierarchy this week in a coordinated action over allegations of widespread abuse in the northwestern region.
- 'Direct assault on democracy' -
At least one million Uyghurs and people from other mostly Muslim groups have been held in camps there, according to rights groups, who accuse authorities of forcibly sterilising women and imposing forced labour.
Conservative MPs Nusrat Ghani, Tim Loughton, Tom Tugendhat and Neil O'Brien, and peers Helena Kennedy and David Alton, were also on the list announced by China on Friday.
In a joint statement, Tugendhat and O'Brien called the sanctions "profoundly sinister" for targeting elected lawmakers.
"As British legislators this will not actually affect us hugely, but the point of Beijing's actions is to make others feel threatened, and to have a chilling effect on business people in particular," they said.
Tugendhat further told the BBC that the move was "a direct assault on British democracy and an attempt to silence the people that the British people have chosen to speak for them."
Ghani told BBC radio that she "won't be intimidated".
"This is a wake-up call for all democratic countries and lawmakers that we will not be able to conduct our day-to-day business without China sanctioning us for just attempting to expose what's happening in Xinjiang."
Organisers of a people's tribunal in London into alleged abuses against the Uyghurs said the sanctions would not affect its work or ruling.