Leigh expansion and Hildenborough embankment scheme

The Leigh expansion and Hildenborough embankment scheme will increase the capacity of the existing Leigh Flood Storage Area (FSA) and construct a new flood embankment in Hildenborough. The Environment Agency are responsible for the delivery of this scheme, and are working in partnership with us and Tonbridge and Malling Borough Council.

The Environment Agency will increase the storage capacity of the existing Leigh FSA by carrying out works which will allow water within the FSA to be stored to a greater depth. They will also construct an embankment in Hildenborough to prevent flooding from the River Medway. In total, the works will reduce flood risk to approximately 230 more homes, 1,430 properties in total.

Watch this short animation to find out more about how the Leigh FSA works to reduce downstream flood risk.

Scheme value

The Leigh expansion and Hildenborough embankment scheme is a £21.3 million project to be constructed between 2021 and 2023. The scheme is partially funded by £2.349 million of the Local Growth Fund. Other sources include:

  • approximately £16 million of Flood Defence Grant in Aid from the Environment Agency
  • £500,000 from Tonbridge and Malling Borough Council
  • £2.5 million from us.

The existing Leigh FSA currently reduces flood risk to 1,200 homes and 100 businesses in Tonbridge. However, it cannot prevent flooding in very large events and the area still suffered serious flooding, affecting over 300 homes and over 100 local businesses.

In addition to the flood risk to existing properties, considerable parts of the borough are constrained by the risk of flooding. Investment is needed to increase the capacity of the storage area in order to achieve greater protection for existing homes and businesses and to unlock new residential and commercial development.

Formal decision

The decision by the SELEP Accountability Board to grant £2.349 million Local Growth Funding for the Leigh FSA scheme was made on the 14 September 2018.

The scheme is continuing to progress as planned, despite some disruption from COVID-19. A key piece of work through 2019 and 2020 has been a consultation with landowners and organisations about the proposal to increase the maximum stored water level within the Leigh FSA during times of flood.

Increasing this maximum stored water level requires permission from the Secretary of State for Environment, Food and Rural Affairs. Over the last 18 months the Environment Agency has been talking to local organisations and landowners who are affected by the increase in stored water level to explain what it means for them and discuss any concerns they have. The Environment Agency submitted a request to the Secretary of State to increase the stored water level in the Leigh FSA in early June 2020 and will receive a decision in due course.

Alongside this, the Environment Agency has been working with Network Rail to investigate whether increasing the stored water level will affect the railway embankment. These investigations have found that no additional works are needed. This means that the combination of concrete walls and additional earth embankments which were proposed at the November 2018 drop in sessions will not be necessary.

This is great news for the environment as the scheme will use less concrete, the works will require less construction traffic, and the scheme will result in fewer carbon emissions. It’s also great news for local users of the area as there will be less disruption from construction activities and much of the area around the FSA will remain as it is now.

The Environment Agency are now working on the planning applications for the construction works.


  • Leigh FSA planning application submission – August 2020
  • Design activities concluded - Winter 2020/21
  • Hildenborough planning application submission – Winter 2020/21
  • Construction begins – Spring 2021
  • Construction ends - Autumn 2023.

If you have any questions or would like to request more information about this scheme, email LEHES@environment-agency.gov.uk.

Funded by

The government Growth Deal provides money to the South East Local Enterprise Partnership, funding projects which drive Kent’s economic and business growth.