Dowden is expected to make a statement Monday, a government official said, declining to confirm whether the deputy PM will also announce reprisals including sanctions.
There has been growing anxiety about China’s alleged espionage activity in Britain, particularly after it emerged last year that a parliamentary researcher was arrested on suspicion of spying for China.
The government said last year that Chinese spies are targeting British officials in sensitive positions in politics, defense and business as part of an increasingly sophisticated spying operation to gain access to secrets.
The Chinese Embassy in London did not immediately respond to a request for comment.
Last year, the embassy accused the British government of “making groundless accusations” when the head of MI5 accused China of carrying out an espionage campaign on an “epic scale.”
Britain’s domestic intelligence service MI5 has said it is now running seven times as many investigations into Chinese activity as it did in 2018 and plans more.
In 2022, MI5 issued a rare security alert, warning members of parliament that a suspected Chinese spy was “involved in political interference activities” in Britain.