Thirty London landmarks were lit up in purple last night to mark Tuesday’s opening of the Elizabeth Line, one of the biggest infrastructure projects ever undertaken in Britain. The new rail line which will link Reading to the west of England with Essex to the east, via central London has been described as a game changer by London transport commissioner Andy Byford. But four years late and almost $5 billion over budget, is it worth it? The World’s Europe correspondent Orla Barry reports.