| 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 Sites of Special Scientific Interest (SSSIs), Areas of Outstanding Natural Beauty (AONBs), National Nature Reserves (NNRs), Local Nature Reserves (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 Lord President of the Council | |||
| 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 |