The major British cities outside London, with some exceptions, lack the large-scale, integrated public transport systems that are a feature of comparable cities on the continent, such as Lyon, Rotterdam, Cologne or Barcelona. Perhaps more surprisingly, there is also a growing gap with many mid-size U.S. cities, which have seen significant light-rail development over the past decade. By any measure, the rollout of tram and other mass-transit city region schemes in Britain has been disappointing over the past 20 years. Their absence is holding back growth and productivity.