The £42m Leigh flood scheme is finished: 23% more water held back, cutting flood risk for 1,870 homes and 575 businesses in Tonbridge and Hildenborough.
The expanded Leigh flood storage area is finished. The £42 million scheme upstream of Tonbridge, with a new embankment at Hildenborough, has officially opened. It reduces flood risk to 1,870 homes and 575 businesses in Tonbridge and Hildenborough.
The Environment Agency announced the opening on 30 September. Tonbridge and Malling Borough Council published the same announcement the day before. (Environment Agency; Tonbridge and Malling Borough Council)
What has changed at Leigh
The flood storage area sits on the River Medway between Leigh and Penshurst, a few miles west of Tonbridge town centre. It is a 1.3km earth embankment, 5 metres high, with a control structure holding three steel gates. When a flood is forecast, the gates hold water back upstream so the river runs lower through Tonbridge.
The upgrade lets it hold more:
- the maximum stored water level at the control structure has gone up by 55cm
- capacity is up by around 23%, to about 7.4 million cubic metres
- that is roughly 2,880 Olympic swimming pools, in the Environment Agency’s comparison
- three new 12.5 tonne gates replace the old ones, each lifted in by a 300 tonne crane
- new lifting and electrical systems, and platforms for easier maintenance
- an eel pass, so eels, a protected species, can get past the structure
The work took three years. The storage area stayed in use throughout, so it could still be closed if a flood came. The Environment Agency says the upgrade keeps the structure working for the next 50 years.
The original barrier was finished in 1982. It has been operated 75 times between 1981 and this summer. An Environment Agency operator watches river levels and forecasts around the clock and decides when to close the gates. (Environment Agency)
Hildenborough’s new embankment
Hildenborough floods for a different reason. When the Medway is high, it backs up into the Hawden Stream. About 180 Hildenborough homes were affected by flooding in 2013.
The new defences there are:
- a 98-metre embankment across the floodplain
- a new pumping station on the Hawden Stream
- a sheet-piled wall
Together they stop the Medway backing up into the village. The Environment Agency says this does not raise flood risk anywhere else. (Environment Agency)
Who paid, and what it cost
The scheme cost about £42 million to design and build. The Environment Agency puts its benefit to communities downstream at more than £155 million.
The funding came from:
| Funder | Amount |
|---|---|
| Government (Flood Defence Grant in Aid) | £36,616,500 |
| Kent County Council | £2,500,000 |
| South East Local Enterprise Partnership | £2,298,500 |
| Tonbridge and Malling Borough Council | £500,000 |
| Local levy funding | £85,000 |
The final cost is higher than the last published estimate. The Environment Agency’s scheme page, last updated in July, still estimated the cost at £36.14 million. (Leigh expansion and Hildenborough embankment scheme)
Why it was built
Tonbridge and Hildenborough have flooded from the Medway in 1960, 1963, 1968, 1974, 2001, and in 2013 and 2014. The 1968 flood was the one that led to the original barrier.
The government approved the higher water level in September 2021. VolkerStevin was appointed to build it in spring 2022. Tonbridge and Malling Borough Council granted planning permission for the Hildenborough embankment in November 2022. (Leigh expansion and Hildenborough embankment scheme)
Council leader Matt Boughton said the scheme would help “reduce the likelihood of severe flooding in Tonbridge, Hildenborough and other villages downstream” for generations. Simon Curd, the Environment Agency’s flood risk manager in Kent, called it “a highly complex engineering project, delivered while the flood storage area remained operational”.
What it means for you
- Lower risk is not no risk. The Environment Agency says flood defences cannot remove the risk completely. If you live near the Medway or the Hawden Stream, keep your flood plan.
- Sign up for flood warnings. They are free by text, phone or email through GOV.UK’s flood warning service.
- Check your own address. The long-term flood risk checker shows the risk for your postcode. It may take time to reflect the new defences.
- The town walls still matter. The Environment Agency says Leigh works as part of a wider system, with the Tonbridge town walls and the natural floodplain at the sports pitches.
Sources: Environment Agency, New flood scheme opens to protect Tonbridge and Hildenborough, 30 September 2026; Tonbridge and Malling Borough Council news, 29 September 2026; Environment Agency scheme page.
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