| Key functions | Non-tidal river (above Teddington Weir) | Tidal river (London area) | Tidal river (below London to sea) | Central Government |
|---|---|---|---|---|
| Conservancy of River | Thames Conservancy | Port of London Authority (PLA). London County Council (LCC) water quality surveys | PLA | Ministry of Housing and Local Government (MHLG) |
| Flood Protection | Riparian local authorities Thames Conservancy (Thames and other 'main rivers') | London County Council (LCC), Rivers & Drainage Committee (1950-65) responsible for 'London Excluded Area' Riparian London Boroughs Lea Conservancy Catchment Board some functions in Lea catchment | Riparian local authorities Essex River Board ('main rivers') Kent River Board ('main rivers') PLA some duties | MHLG Ministry of Agriculture, Fisheries & Food (MAFF): Land Drainage & Water Supplies Division |
| Land Drainage | Thames Conservancy ('main rivers') | LCC, Rivers & Drainage Committee (1950-65): responsible for 'London Excluded Area' London Boroughs | Essex River Board ('main rivers') Kent River Board ('main rivers') Internal Drainage Boards for (ordinary watercourses), e.g. Lower Medway IDB and Upper Medway IDB) | MAFF: Land Drainage & Water Supplies Division |
| Residual role of Commissioners of Sewers for Levels of Havering, Dagenham, Ripple, Barking, East Ham, West Ham, Leyton, Walthamstow, Bromley, East Marsh | ||||
| Navigation / Pilotage | Thames Conservancy | Port of London Authority (PLA) Pilotage: Trinity House | Ministry of Transport | |
| Pollution Control | Thames Conservancy | PLA | MHLG | |
| Port / Harbour Authority | Not applicable | PLA | Ministry of Transport | |
| Recreation | Thames Conservancy | PLA (Harbour Service) as part of navigation duties | MHLG | |
| Riverside Planning | Riparian local authorities | Riparian London Boroughs (x14) Strategic planning: LCC | Riparian local authorities | MHLG |
| Note: nature protection sites include (SSSIs), (AONBs), (NNRs), (LNRs). For the Greater Thames estuary area e.g. this included the SSSI at South Thames Estuary and Marshes, first notified in 1951 | Nature Conservancy (1949-65), responsible to | |||
| Sewerage | Local authority undertakings | LCC Local authority undertakings | Local authority undertakings | MHLG |
| Water Supply | Local authority undertakings, joint boards, statutory private companies Thames Conservancy some powers over water resources | Metropolitan Water Board | Local authority undertakings, joint boards, statutory private companies | MHLG Natural resources planning: MAFF |