What do Theresa May and Andy Burnham have in common with Michel Barnier, François Bayrou and Emmanuel Macron? All five were admirably honest with the public about the trade-offs inherent in financing an ageing society, and all five were duly punished for their candour by the public, the press, opposition politicians or all three.The past two decades of French and British politics are a graveyard of proposals to slow the upward ratchet of spending on growing elderly populations. The same two decades of French and British fiscal balances show the results. Public disbursements to older citizens have climbed higher and...