"Parliament was advised last week by the National Cyber Security Centre, part of intelligence agency GCHQ, that Zoom should only be used for public business.

A parliamentary source said those involved were advised Zoom ought not be used for classified business and there was an explicit warning from NCSC “not use it to talk about things detrimental to the interests of China”."

https://www.theguardian.com/uk-news/2020/apr/24/uk-government-told-not-to-use-zoom-beca...