Headbolt Lane Biodiversity Net Gain

Biodiversity Net Gain (BNG) is an approach to development, land and marine management that leaves biodiversity in a measurably better state than before the development took place.
Currently, although certain sites are protected, there are limited mechanisms to value, maintain, enhance or create wider habitats. As a result, habitats continue to be lost to development, reducing nature's ability to connect and thrive. Under the Environment Act 2021, all planning permissions granted in England (with a few exemptions) will have to deliver at least 10% biodiversity net gain from an as yet unconfirmed date, expected to be in November 2023. BNG will be measured using Defra’s biodiversity metric and habitats will need to be secured for at least 30 years.

Network Rail committed to providing a Net Positive Biodiversity gain for a new train station at Headbolt Lane in Kirkby. Network Rail, and their Principal Contractor Buckingham Group Contracting, identified Mersey Rivers Trust as a partner to deliver BNG, and other environmental, social and economic benefits to the local area. 

The project is the first of its kind in the area to use the BNG metric and is piloting the methodology of how BNG may work in the future and what the challenges are to implement BNG.


Network Rail's Biodiversity targets


Identify and prioritise interventions

A desktop study helped us to identify locations close to the new development which could benefit from habitat improvement works. Site walkovers were then undertaken to ground-truth and identify specific interventions.

Complete biodiversity calculations

Baseline habitat surveys were completed at each site and biodiversity credits calculated using the latest version of the DEFRA metric.

Feasibility and surveys

Early discussions with the landowner and other key stakeholders was important to ensure the project would be feasible. Relevant permits, permissions and agreements were produced and surveys undertaken, including ecology (Water Vole, Great-crested Newts, Bats), utilities, UXO and contaminated land.


Basic sketches produced by MRT staff were turned into full designs by a specialist consultancy. The designs could then be handed over to a contractor to aid delivery. The design includes a drawing plus documentation around project risks to both people and the environment.

Wider stakeholder engagement

Stakeholders were engaged at every step of the process but this was an opportunity to share the full designs with the landowner and members of the public. Community consultations were held as a chance for local residents to learn more about the project and ask questions.


A series of interventions are to be delivered at 6 parks across Kirkby, including wetlands, ponds, hedges, wildflower meadows and river restoration. Below is more information about the works at each site...

Mercer's Dell baseline habitat assessment


Water Vole survey

Mercer's Dell

Himalayan Balsam control, creation of reed beds within Kirkby Brook, rewilding mown grassland and planting hedging along the park boundary.

Mill Dam Park

Creation of a large offline wetland pond with a mosaic of habitats including wet woodland, bogs, deep water and reed beds.

Millbrook Millennium Green

Re-landscape and manage a series of existing ponds and reed beds.                                                                 

Saxon Green

Himalayan Balsam control, wildflower planting, rewilding and wetland management.                                                              

Northwood Forest Hills

Re-landscape and manage a series of existing ponds and wet woodland, Himalayan Balsam control and wildflower planting.

Eddie McArdle Fields

Himalayan Balsam control, creation of reed beds within Kirkby Brook and re-naturalise river bed by removing concrete half-pipe.

Works to be complete by December 2023.



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