The head of the GCHQ intelligence agency has warned that Russia is going after critical infrastructure and democracy in the UK.

Anne Keast-Butler also used the inaugural GCHQ annual lecture at Bletchley Park to say the threat of this "daily hybrid activity" leading to a wider conflict is as "high as I’ve ever seen it".

Her warning comes days after an RAF jet carrying the UK's defence secretary John Healey had its signal jammed near the Russia border.

Why is Moscow allegedly carrying out these hybrid attacks and what is being done to tackle them?

Gareth Barlow discusses how severe the Russia threat is with Sky's military analyst Professor Michael Clarke.