The Chinese ambassador to the UK has been banned from attending an event in the British parliament because China imposed sanctions on MPs who highlighted alleged human right abuses in Xinjiang.
China placed the sanctions on nine British politicians, lawyers and an academic in March for spreading what it said were "lies and disinformation" over the treatment of Uighur Muslims in the country's far west.
Lindsay Hoyle, the Speaker of the House of Commons, and John McFall, the Speaker of the House of Lords, stepped in to prevent Zheng Zeguang from speaking at an event in parliament.
"I regularly hold meetings with ambassadors from across the world to establish enduring ties between countries and parliamentarians," Mr Hoyle said.
"But I do not feel it's appropriate for the ambassador for China to meet on the Commons estate and in our place of work when his country has imposed sanctions against some of our members."
A Chinese embassy spokesperson criticised the move.
"The despicable and cowardly action of certain individuals of the UK parliament to obstruct normal exchanges and co-operation between China and the UK for personal political gains is against the wishes and harmful to the interests of the peoples of both countries," a Chinese statement said.
Mr Hoyle said he was not banning the Chinese ambassador permanently but only while the sanctions remained in place.
Richard Graham, chairman of the All Party Parliamentary China Group, had given an invitation to Mr Zeguang during the summer, the Daily Telegraph said.
Mr Graham did not respond to a request for comment.
The All Party Parliamentary China Group declined to comment.
China sanctioned five UK MPs including former Conservative Party leader Iain Duncan Smith and Tom Tugendhat, the chairman of parliament's foreign affairs committee.
The targeted individuals and their immediate family members are prohibited from entering Chinese territory and Chinese citizens and institutions are prohibited from doing business with them.
China took the action after the UK, the United States, the European Union and Canada imposed parallel sanctions on senior Chinese officials accused of the mass internment of Uighurs in Xinjiang.
Tim Loughton, a Conservative politician targeted by the sanctions, welcomed the decision to bar the ambassador from the event.
He said China could not think "they can shut down free speech by parliamentarians in a democracy".
At the time the sanctions were imposed, the UK condemned the move as an attempt by China to stifle criticism.
Officials in London and Beijing have been trading angry words over a range of issues, including China's reforms in former British colony Hong Kong and China's trade policy.
Activists and UN rights experts say at least a million Muslims have been detained in camps in Xinjiang.
The activists and some foreign politicians accuse China of using torture, forced labour and sterilisations.
China's government has repeatedly denied all accusations of abuse and says its camps offer vocational training and are needed to fight extremism.
