Priti Patel MP interview on Chinese Spy in UK Parliament

The transcript discusses the current level of action that state security services, policing, and CPS can take, which is currently under criminal thresholds. An alert is issued to put MPs on notice about an individual's activities. The aim is to take future legal and criminal actions if thresholds are crossed.

What type of activities has the individual been involved in according to the alert?

What is the significance of crossing certain thresholds in this context?