Britain's domestic spy service MI5 has told the House of Commons speaker that the Chinese Communist Party has been employing a woman to exert improper influence over lawmakers.
Speaker Lindsay Hoyle said in an email to lawmakers on Thursday that MI5 had found that the woman "has been engaged in political interference activities on behalf of the Chinese Communist Party, engaging with members here at parliament".
She "has facilitated financial donations to serving and aspiring parliamentarians on behalf of foreign nationals based in Hong Kong and China", the email added.
Hoyle said the woman had been involved with the now disbanded all-party parliamentary group, Chinese in Britain.
Britain's interior minister Priti Patel said it was "deeply concerning" that an individual working on behalf of the Chinese Communist Party had targeted lawmakers. She said the individual was identified because of the "strong structures the United Kingdom has in place to identify foreign interference".
The Chinese embassy in London did not immediately respond to a request for comment.
Iain Duncan Smith, a former leader of Britain's governing Conservative Party who has been sanctioned by China for highlighting alleged human right abuses in Xinjiang, called for an urgent update from the government on the issue.
He questioned why the woman had not been deported and called for a tightening of the accreditation process for people gaining access to parliament, which he said was too lenient.
Former defence minister Tobias Ellwood told parliament: "This is the sort grey-zone interference we now anticipate and expect from China."
Britain's relations with China have deteriorated in recent years over issues including Hong Kong and Xinjiang.
Last year MI5 urged British citizens to treat the threat of spying from Russia, China and Iran with as much vigilance as terrorism.
British spies say China and Russia have each sought to steal commercially sensitive data and intellectual property as well as to interfere in domestic politics and sow misinformation.
The Chinese ambassador to Britain was banned from attending an event in the British parliament last year because Beijing imposed sanctions on lawmakers who highlighted alleged human right abuses in Xinjiang.
China placed the sanctions on nine British politicians, in March last year for spreading what it said were "lies and disinformation" the over the treatment of Uighur Muslims in the country's far west.