Ensuring energy security is a central goal of energy policy in most countries. The UK is no exception. Throughout the increasingly rapid changes in the energy sector over the past few years, energy security has remained high on the policy agenda. This winter has been a good example. Whilst gas demand has fallen significantly in the last decade, recent cold weather and infrastructure problems have tested the resilience of the UK gas system. This report explores how the security of the UK energy system could change in the future. UK energy security will be shaped by a range of factors including action to reduce emissions, technological change and shifting geopolitics – including the UK’s changing relationship with the EU due to Brexit. @en