tl;dr: UK electricity generation per person peaked in 2003 and has since fallen by over a third, returning to late-1960s levels, even as global per-capita generation has grown 50% this century. Deindustrialization accounts for part of the drop—industrial electricity use is down a quarter since 2005—but residential and commercial consumption has fallen by the same amount, driven largely by efficiency gains like LED lighting and appliance standards. Rising imports (from 1% of demand in 2010 to 9% in 2025) explain only a small portion of the decline.