In September, a case involving two men accused of spying for China collapsed in controversial circumstances.

One of the men was a parliamentary researcher. Both men denied wrongdoing.

The head of the Crown Prosecution Service said the case collapsed because it could not get evidence from the government referring to China as a national security threat.

However, some legal experts have questioned whether the CPS would have needed this evidence to go ahead with the prosecution.

Concerns about China's influence over British politics have been growing in recent years.

In 2022, MI5 issued an"interference alert" about the activities of alleged Chinese agent Christina Lee, who was believed to have infiltrated Parliament. Ms Lee denied the allegations.

China is also believed to be gathering bulk data on the UK population including accessing data sets that contain financial, personal or health information.

Earlier this year, MI5 boss Ken McCallum warned that Chinese state actors posed a daily national security threat to the UK.