By Sam Dumitriu London built the world’s first underground railway and the beautiful, beloved mansion blocks of Chelsea and Marylebone. We can do it again, says Sam Dumitriu Rents in London are now so high that a one bed in the capital will set you back more than a three bedroom will in any other region of England. And what do Londoners get for those sky-high rents? Less space than ever before. In fact, the amount of floorspace per person in London has fallen for renters from 30sq m in 1996 to 25sq m in 2018. Rents are unaffordable for a simple reason: we haven’t built enough homes to meet ris…