No one ever warned me quite how hectic my 11 years as a clerk in the House of Commons would be, but I still felt fortunate when I saw how much work even the youngest Treasury staffers were tasked with. The Treasury’s civil service fast-stream programme is notoriously (and understandably) competitive, and once you’ve completed it you wouldn’t be expected to last more than a few years without becoming completely exhausted. It’s when you realise how much responsibility you’ll be given that the early-onset Whitehall fatigue syndrome begins to make sense. If you arrive at the Treasury in your early twenties, you’ll quite quickly be operating at a very high policy level: you’ll be making decisions or making recommendations for those decisions with a macroeconomic impact. During the financial crisis, records submitted to clerks like me showed that we had relative newcomers making the really important phone calls to RBS and Goldman Sachs. The Treasury is very much where you want to be when you...