https://www.theguardian.com/world/2020/apr/27/uk-to-name-scientific-advisers-on-emergency-coronavirus-group-sage

Including the:

• Scientific Advisory Group for Emergencies (Sage),
• Scientific Pandemic Influenza Group on Modelling (Spi-M) sub-group
• Scientific Pandemic Influenza Group on Behaviours (Spi-B) sub-group and
• New and Emerging Respiratory Virus Threats Advisory Group (Nervtag)

Guardian article says:

Vallance said there was interest in the Sage meetings across Whitehall from early on. Many people were listening in from “various departments”, but they were not part of the general discussion. “That does include people from No 10 and, yes, occasionally they ask questions.”

Political advisers from Downing Street have never attended Sage meetings before, according to a review of all publicly available minutes of meetings over the last decade.