The Marylebone LEN was established in July 2016 and is set on and around Marylebones busy shopping high street, with narrow pavements lined by boutique stores and cafes that spill out onto the pavements. The aim is to improve air quality and the public realm by reducing vehicle dominance, introducing green infrastructure. The site had traditional gully connections draining large catchments (highway and pavements), with the worst gully draining over 1,600m 2 – ten times the recommended design standard.