Biodiversity Net Gain (BNG) in Hampshire
Planning-ready BNG assessments for Hampshire— verified baselines, Metric 4.0 scoring and proportionate uplift strategies for a predictable planning route.
Do You Need a Biodiversity Net Gain Assessment in Hampshire?
Most developments in Hampshire now require a mandatory 10% biodiversity net gain under the Environment Act 2021.
Local planning authorities expect clear baseline data, a defensible Metric 4.0 calculation and a proportionate uplift strategy before your application can progress. Shropshire’s landscape is shaped by lowland farmland, wet meadow systems, hedgerow-rich pastures, woodland belts, upland edges, and extensive river corridors including the Severn and Teme. These factors strongly influence how LPAs interpret BNG.
Local landscape features affecting BNG expectations across Hampshire include:Â
- chalk grassland and downland around Winchester, Test Valley and East HampshireÂ
- coastal, tidal and estuarine habitats along Portsmouth, Southampton and the SolentÂ
- woodland networks across the New Forest and northern HampshireÂ
- lowland heathland systems across the northeast (e.g., Yateley, Bordon, Farnborough fringe)Â
- river valleys along the Test, Itchen, Avon and LoddonÂ
These patterns influence how uplift proposals are evaluated during planning.Â
We support projects across: Winchester, Southampton, Portsmouth, Basingstoke, Eastleigh, Fareham, Gosport, Andover, Havant, Ringwood, New Forest and all surrounding areas.Â
Why Hampshire Planners Request BNG Evidence Early
Hampshire LPAs often request BNG evidence early because the county’s diverse mix of grassland, hedgerow networks, riparian corridors and upland edge habitats can lead to condition scores shifting during design development. Early clarity reduces redesign and prevents later uplift recalculation.
Local Case Insight
BNG Requirements — Delivered in a Predictable Sequence
We produce planning-ready BNG Assessments aligned to Hampshire’s policy expectations.
Key BNG Deliverables for Hampshire Projects
For Hampshire schemes, every planning-ready BNG Assessment includes:
• defensible Metric 4.0 calculation
• proportionate, locally-appropriate uplift strategy
• clear validation-ready reporting
• optional HMMP and Biodiversity Gain Plan integration
These deliverables are structured to satisfy Hampshire LPAs while keeping your BNG route proportionate to the scale of development.
Step 1
Habitat baseline surveys
Year-round, with optimal survey seasons
Step 2
Metric 4.0 calculations
 Completed once habitat data is verified.Â
Step 3
Uplift strategy development
Aligned with design progression and layout refinement.
Step 4
Integration with Other Surveys
Only if needed. PEA, EIA, and Protected Species surveysÂ
Next Steps
Contact us and we’ll confirm exactly what your site requires and support a planning-ready, proportionate route forward.Â
FAQ - BNG in Hampshire
What is a Biodiversity Net Gain assessment in Hampshire?
A Biodiversity Net Gain assessment establishes the baseline ecological value of a site using the statutory Biodiversity Metric and models the proposed development to confirm whether at least 10 percent measurable uplift can be achieved in accordance with national legislation.
Are developments near the New Forest or South Downs National Park subject to Biodiversity Net Gain?
Yes. Development within or near sensitive landscapes must still comply with statutory Biodiversity Net Gain requirements. The assessment must accurately quantify baseline habitats and demonstrate compliant uplift.
How do chalk stream corridors affect BNG assessments?
Sites near the River Test, River Itchen or other chalk streams may contain riparian habitats of higher ecological value. The baseline must be carefully surveyed and quantified to ensure realistic modelling within the Biodiversity Metric.
When is a BNG assessment required in Hampshire?
A BNG assessment is required where development falls within the statutory scope of mandatory Biodiversity Net Gain legislation. This includes residential, commercial, mixed use and strategic allocation sites.
How are coastal or estuarine fringe sites assessed?
Where sites are influenced by coastal habitats, the assessment must correctly classify and quantify grassland, scrub or wetland habitats before modelling development proposals.
Can large strategic housing sites achieve 10 percent uplift on site?
Many strategic allocations can achieve uplift through woodland planting, meadow creation and sustainable drainage features. However, early feasibility modelling is critical to confirm that the required uplift is realistically deliverable.
How long does a Hampshire BNG assessment typically take?
Timescales depend on site size and habitat complexity. Larger mixed use or strategic sites often require iterative modelling alongside masterplanning to achieve compliant outcomes.
What if a site cannot meet the 10 percent requirement on site?
If modelling identifies a biodiversity unit shortfall, the applicant may secure registered off site biodiversity units to meet statutory requirements.
Which authorities review BNG assessments in Hampshire?
Depending on site location, Biodiversity Net Gain assessments are reviewed by authorities such as Winchester City Council, Basingstoke and Deane Borough Council, East Hampshire District Council or Southampton City Council.
Planning guidance for Winchester City Council can be accessed at:
https://www.winchester.gov.uk/planning
How can ProHort support Biodiversity Net Gain assessments in Hampshire?
ProHort undertakes detailed habitat surveys and robust Biodiversity Metric modelling tailored to Hampshire’s chalk stream and coastal influenced context. We provide early feasibility advice, clear unit calculations and defensible planning documentation.
