What happens when the grey zone becomes a war zone and what might future wars look like, with hypersonic missiles, artificial intelligence and cyber changing calculations?These are questions Sky News journalist Deborah Haynes explores in this episode, in part, by looking at Russia’s annexation of Crimea and the conflict in eastern Ukraine.She also talks to General Sir Nick Carter, the head of Britain’s armed forces, about what he thinks is the gravest threat to the UK and about how the military is adapting to operate in the grey zone.Guests:General Sir Nick Carter, Chief of the Defence StaffGeneral Sir Richard Barrons, former head of Joint Command, now Strategic CommandEmine Dzhaparova , First Deputy Foreign Minister of UkraineSergei Markov, political scientist and former member of the Russian parliamentKeir Giles, senior consulting fellow at Chatham HouseOrysia Lutsevych, head and research fellow, Ukraine Forum, Russia and Eurasia Programme, Chatham HouseCredits:Written and narrated by Deborah Haynes Edited and produced by Chris ScottProduction support from Sophia McBide and Michael GreenfieldThe Head of Sky News Radio is Dave Terris