It is September 2016. The UK is in the grip of austerity following a second banking collapse. Oil supplies have all but dried up. The priority of a provisional government is energy - energy to power transport, industry, agriculture, homes, schools and hospitals. A skeleton rail service already operates with the aid of coal-fired steam locomotives requisitioned from preservation societies. There is no international credit. Trade - where it occurs - is by barter. Energy is the new wealth. David Sewell is a retired - but still youthful - engineer passionate about technology as much for its...