TfL’s biggest sustainable urban drainage system (SuDS) was completed around the Marylebone Flyover in 2024. The gardens have a rainfall catchment area of 3,500m2 and can deal with a flood ranging from one in 5 years to one in 20 years. The gardens host 11 new trees, 1,100 plants and shrubs and 2,300 bulbs.
The BID has directly funded the information boards explaining how the gardens and their drainage systems work, biodiversity assets like bee posts and is responsible for the vital maintenance of the gardens, including weeding and re-planting. This ground-breaking arrangement serves as a flagship template for future TfL SuDS.
Local businesses and schools have stepped up to take part in regular litter picks and planting activities, taking joy in seeing the gardens flourish.
TfL completed the safety scheme at the junction of Edgware Road, Sussex Gardens and Old Marylebone Road in February 2026. This scheme saw the benefit of 135 m2 of additional footway plus three additional SuDS or rain gardens added to the northbound slip road, reducing surface water flooding and keeping rainwater from overwhelming drains by holding the water in the gardens themselves. The three new rain gardens cover 143 m2 and were planted with 1,030 bulbs, 517 plants and five new trees. The gardens have capacity to handle a one in ten year storm and have a combined water catchment area of 1,547 m2.
This work complements the new Sustainability Exchange proposed in the third term, with businesses growing their knowledge and appreciation of sustainability and resilience.