Biodiversity Net Gain Units Procurement

Defra intends to purchase Biodiversity Net Gain (BNG) units of a total value of £530,000 (inc VAT). The units must be one or more of the following types of Very High (VH) or High (H) Distinctiveness units, (as defined in The Statutory Biodiversity Metric user guide*): Blanket bog (VH) Fens (upland and lowland) (VH) Grassland - Lowland meadows (VH) Grassland - Upland Hay Meadows (VH) Woodland and forest - Wood pasture and parkland (VH) Grassland - Floodplain wetland mosaic (H) Grassland - Lowland calcareous (H) Grassland - Traditional Orchard (H) Lowland heathland (H) Ponds (Priority) (H) Woodland and forest - Lowland mixed deciduous (H) Woodland and forest - Wet woodland (H) Upland heath (H) Other BNG unit types are not eligible. Units must be supplied from a single registered gain site in England as defined by government guidance at: https://www.gov.uk/guidance/sell-biodiversity-units-as-a-land-manager The following unit types have been excluded: medium or low distinctiveness units because of their lower priority; linear units for reasons of comparability; and unit types with lower availability on the register, in order to avoid causing market scarcity for particular unit types. By requiring units to come from a registered gain site Defra will ensure that the habitat enhancement provided is high quality and legally secured for at least 30 years – meeting the same standards as those required of BNG units purchased by developers. Bidders are required to provide: - The biodiversity gain site registration number associated with the site from which you propose to provide units - Details of the number and type of units you propose to sell - The physical address of the gain site and the signatory to the legal agreement securing the gain site The successful bidder will also be required to provide the following and to enter into a licensing agreement regarding the use and publication of such data equivalent to that already in place for data submitted to the gain site register: - The Biodiversity Metric Excel file associated with the gain site - The geospatial boundary of the gain site, provided as shapefile - Geospatial polygons of individual habitat parcels located on the gain site as baseline and proposed habitats post-intervention, provided as shapefiles. The highest commercial score will be awarded to the bid which offers the greatest number of BNG units for the contract value. Note that the BNG metric already incorporates multipliers for the distinctiveness and strategic significance of habitat (for example, sites identified in Local Nature Recovery Strategies) allowing bids to be evaluated based on a comparison of the number of units offered. In the event that bids receive an identical Total Score, Defra will consider the current availability of registered units of the specific habitat type offered, with a preference for purchasing those which are more widely available. The register is strictly to be used to record allocation of gain site land for the purpose of mandatory biodiversity net gain. The chosen supplier must ensure the gain site register record is amended to reflect the removal of habitat used to generate the units. Proof of application to amend must be submitted within one week of a completed sale. The habitat used to supply the units must not be removed from the securing legal agreement to manage the site for the agreed conservation purposes (s106 or Conservation Covenant) and should remain subject to the maintenance and monitoring obligations outlined in that agreement. Defra will carry out periodic checks via the Local Planning Authority / Responsible Body to ensure that these agreements remain in place and that the results of monitoring are satisfactory. To enable Defra to ensure the results of monitoring are satisfactory and to support policy evaluation of Biodiversity Net Gain, Defra require copies of all monitoring reports and may at times require access to support wider policy evaluation activities. This procurement forms Defra’s first investment of income from the sale of statutory BNG credits into habitat enhancement. Details will be published in the next annual report on BNG statutory credits in spring 2026. This procurement does not set any precedent for how BNG credit income will be invested in future years. Future strategy will depend on the volume of credit sales and market conditions. *https://assets.publishing.service.gov.uk/media/689c5ee17b2e384441636196/The_Statutory_Biodiversity_Metric_-_User_Guide_-_July_2025.pdf