Conscription hasn't been used in the UK for more than 60 years. But comments from top military officials about what could happen if NATO goes to war with Russia have made the possibility of being called up to fight feel closer than it has in generations. General Sir Patrick Sanders, the outgoing head of the British Army, said such a conflict would need to be a "whole-of-nation undertaking", which reignited a debate about defence cuts and volunteering to fight. Here Sky News looks at how the UK has used conscription before, and what military experts and the government say about...