Portsmouth BNG advice
Biodiversity Net Gain in Portsmouth
Plan your Portsmouth development around local habitats, planning requirements and practical biodiversity gains.
ACP Consultants can help with habitat surveys, biodiversity metric calculations and a practical BNG delivery plan for your Portsmouth site.
Local requirements
Portsmouth BNG requirements at a glance
| Check | Practical answer |
|---|---|
| Planning authority | Portsmouth City Council — verify the actual parcel, any special planning jurisdiction and site type |
| Adopted development plan | The Portsmouth Plan adopted 2012, with other extant development-plan documents |
| Specific biodiversity policies | PCS13 — A Greener Portsmouth |
| Emerging plan status | Two separate new-plan exercises exist. The new Portsmouth Local Plan 2040 was submitted on 18 March 2026 and was under examination with autumn 2026 hearing sessions. Separately, the Future Portsmouth Plan 2045 preparation formally began 14 July 2026, with its early scoping process. Neither is adopted as at 10 November 2026, so the adopted 2012 Portsmouth Plan remains operative. |
| LNRS | Hampshire Local Nature Recovery Strategy, Published 8 December 2025; Hampshire County Council |
| Statutory BNG | Normally at least 10% for eligible applications; exemption and application date checks are essential |
| Protected sites | Independent Habitats Regulations or protected-species evidence where a credible impact pathway exists |
Planning authority and policy
Local planning requirements for Portsmouth
Confirm the planning authority
Portsmouth City Council is the unitary planning authority for the city. Hampshire’s LNRS includes Portsmouth, while ordinary planning applications follow the city’s own adopted policies.
See BNG in Hampshire and the South East regional guide.
Use the adopted development plan
The Portsmouth Plan adopted 2012, with other extant development-plan documents. Relevant policies include PCS13 — A Greener Portsmouth.
The submitted Local Plan 2040 remains under examination, with further hearings scheduled in November 2026. The Future Portsmouth Plan 2045 is a separate preparation process. The 2012 plan remains adopted.
Establish the gain target
Eligible development normally needs at least 10% statutory gain. Establish the applicable target using current national policy, any relevant site-allocation policy and existing permission.
Plan habitat retention, suitable enhancement and long-term management alongside the site layout. Check the national biodiversity planning policies when establishing obligations.
Check dates and exemptions
For applications from 6 August 2026, sites up to 0.2 hectares may qualify for an exemption if no onsite priority habitat is adversely affected.
Householder, de minimis, temporary-development and transitional rules have their own conditions. Record the application date, site area and supporting habitat evidence.
Use the BNG exemptions guide to identify the relevant route.
Nature recovery and local geography
Local habitats and nature recovery in Portsmouth
Use the local nature recovery map
The published Hampshire Local Nature Recovery Strategy provides priorities and mapped opportunities for habitat recovery. It was published on 8 December 2025.
For Portsmouth, consider Portsmouth and Langstone Harbour margins, Farlington Marshes, Portsdown Hill and urban green spaces. Match the actual site location and proposed habitat to a relevant recovery measure.
Local habitats to consider in Portsmouth
Use the landscape context to scope the survey, then record the habitats actually present within the site boundary.
| Local setting | Potential habitat or evidence issue |
|---|---|
| Portsmouth Harbour and Langstone Harbour | Intertidal mudflat, saltmarsh, estuarine birds and adjacent functionally linked land, where project impact pathways exist. |
| Farlington Marshes and coast | Coastal grazing habitat, bird roosting and protected-site sensitivities; some projects may need HRA/recreational mitigation. |
| Portsdown Hill and wooded slopes | Chalk grassland, scrub, woodland and connected tree habitat; verify habitats on site rather than relying on place names. |
| Urban Portsmouth regeneration | Gardens, urban parks, waterfront trees, planted boundaries and biodiversity-sensitive green roofs can contribute to BNG. |
Plan protected-site and species evidence
Harbour and coastal proposals may affect designated bird habitats, functionally linked land or recreational pressure. Use the site boundary and actual impact pathways to scope Habitats Regulations evidence.
Bird Aware Solent contributions address recreational effects on protected birds where applicable. Assess any nutrient, species and coastal requirements separately from the statutory habitat metric.
Planning and delivery
Preparing evidence and delivering biodiversity gain
Prepare the habitat baseline and metric
Start with the site’s habitat baseline and condition. Use the appropriate statutory metric; the Small Sites Metric is suitable only where its eligibility conditions are met.
In Portsmouth, survey Portsmouth and Langstone Harbour margins, Farlington Marshes, Portsdown Hill and urban green spaces where these occur within or affect the proposal. Record the actual habitat condition and relevant watercourse evidence.
See BNG assessments and habitat surveys, habitat condition assessment and Small Sites Metric assessments.
Prepare the planning submission
Confirm the planning authority, application date, relevant policies and whether statutory BNG applies. Then agree a proportionate submission scope with the council.
- An applicability or exemption explanation supported by site evidence.
- The red-line boundary, baseline habitat plan and metric where required.
- Proposed layout, retained habitats and feasible habitat gains.
- Any protected-species, watercourse, drainage or Habitats Regulations evidence.
Test the layout against local habitat constraints
Retain sensitive habitats and useful connections where possible. Use these questions to compare realistic layout and habitat options.
| Local setting to test | Useful design and survey question |
|---|---|
| Portsmouth Harbour and Langstone Harbour | Can the proposal avoid impacts? Intertidal mudflat, saltmarsh, estuarine birds and adjacent functionally linked land, where project impact pathways exist. |
| Farlington Marshes and coast | What would retaining or improving connectivity involve? Coastal grazing habitat, bird roosting and protected-site sensitivities; some projects may need HRA/recreational mitigation. |
| Portsdown Hill and wooded slopes | Do the existing habitats or species interests restrict the proposed gain type? Chalk grassland, scrub, woodland and connected tree habitat; verify habitats on site rather than relying on place names. |
| Urban Portsmouth regeneration | Can the layout integrate useful green infrastructure? Gardens, urban parks, waterfront trees, planted boundaries and biodiversity-sensitive green roofs can contribute to BNG. |
Choose habitats suited to the site and its long-term management. Match nature recovery measures to the published LNRS map, then calculate all relevant unit categories.
Development and regeneration context
For Portsmouth regeneration, assess existing habitat before setting a zero baseline for previously developed land. Waterfront trees, gardens and planted boundaries can influence the design. Harbour-edge proposals need careful coordination between habitat delivery, access and protected-site requirements.
A practical Portsmouth planning example
Illustration: a constrained urban site loses planted boundaries and grassland. Compare retained trees, suitable roof habitat and realistic landscaping in the metric. If it creates residential accommodation within a relevant Solent mitigation area, establish that separate obligation alongside BNG.
Plan off-site delivery and long-term management
Calculate the genuine shortfall before committing to off-site units. Apply the relevant gain hierarchy, habitat trading rules and location requirements to the proposed delivery route.
Use the Hampshire Local Nature Recovery Strategy to explore habitat opportunities. Confirm registration, suitable units and current availability directly with the proposed supplier.
Read about off-site biodiversity units, Biodiversity Gain Plans and Habitat Management and Monitoring Plans.
Council and delivery costs
What should your Portsmouth BNG budget cover?
Budget for habitat surveys, metric calculations, planning reports and any gain-plan or management work. The scope depends on the site, habitat types and planning stage.
Budget separately for any Bird Aware Solent contribution, nutrient mitigation and specialist coastal evidence. Request the current council tariff and project-specific habitat quotation rather than treating these as one unit price.
Planning evidence
Portsmouth BNG preparation checklist
Free resource: Use the local BNG planning evidence route worksheet. It provides a light, accessible reference to official documents and the difference between BNG and separate ecological duties.
Planning evidence worksheet
Find your Portsmouth planning and evidence route
Use these questions to organise the planning, habitat and delivery information for your site.
Which authority and adopted plan apply?
Portsmouth City Council is the unitary planning authority for the city. Hampshire’s LNRS includes Portsmouth, while ordinary planning applications follow the city’s own adopted policies.
The Portsmouth Plan adopted 2012, with other extant development-plan documents. Relevant policies include PCS13 — A Greener Portsmouth.
How should I treat emerging policies?
The submitted Local Plan 2040 remains under examination, with further hearings scheduled in November 2026. The Future Portsmouth Plan 2045 is a separate preparation process. The 2012 plan remains adopted.
Establish the applicable gain target using current national policy, any relevant up-to-date site-allocation policy and existing permission.
How do I use the nature recovery map?
Match the actual site and proposed habitat to a relevant measure in the Hampshire Local Nature Recovery Strategy. Record the map and survey evidence supporting the metric entry.
Could an exemption apply?
For applications from 6 August 2026, sites up to 0.2 hectares may qualify if no onsite priority habitat is adversely affected. Other exemptions and transitional provisions have separate conditions. Record the development type, date, red-line area and habitat evidence.
Which separate ecological issues matter?
Harbour and coastal proposals may affect designated bird habitats, functionally linked land or recreational pressure. Use the site boundary and actual impact pathways to scope Habitats Regulations evidence.
Bird Aware Solent contributions address recreational effects on protected birds where applicable. Assess any nutrient, species and coastal requirements separately from the statutory habitat metric.
When is the final gain plan needed?
For eligible ordinary applications, the statutory Biodiversity Gain Plan is normally approved after permission and before development starts. Agree earlier planning evidence with the authority and identify feasible management and any off-site delivery route.
Details to gather before an enquiry
Project support
How ACP can help with your Portsmouth project
ACP can help scope the habitat surveys, metric calculations and planning reports needed for your Portsmouth proposal. Early advice is most useful while the layout can still change.
We can consider Portsmouth and Langstone Harbour margins, Farlington Marshes, Portsdown Hill and urban green spaces alongside the site’s planning route and proposed works.
Local planning questions
Frequently asked questions about BNG in Portsmouth
For a site-specific question, discuss your project with ACP.
Which Portsmouth Local Plan is currently adopted?
The Portsmouth Plan 2012 remains the adopted starting point, including biodiversity policy PCS13. The separately submitted Local Plan 2040 had not been adopted as of 10 November 2026.
Is the Future Portsmouth Plan 2045 the same as the examined 2040 Plan?
No. The 2040 plan was submitted in March 2026 and is under examination. The 2045 process began separately in July 2026 and remains at an early stage.
Are Bird Aware Solent contributions the same as BNG costs?
Bird Aware Solent contributions address recreational effects on protected birds for relevant development. BNG assessment and habitat units meet a separate requirement. Use the current council contribution schedule for the actual proposal.
Is Portsmouth included in the Hampshire LNRS?
Yes. Hampshire County Council published the LNRS on 8 December 2025 and its mapping covers Portsmouth and Southampton; both remain separate unitary planning authorities.
Which habitat surveys might a site in Portsmouth need?
Scope the assessment around the habitats and proposed effects. In Portsmouth, relevant settings include Portsmouth and Langstone Harbour margins, Farlington Marshes, Portsdown Hill and urban green spaces. The red-line plan, habitat condition and any water or species pathways determine the survey work.
How should I use the local nature recovery map?
Use the published map to match the site and proposed habitat to a recovery measure. Survey evidence and feasible management then support the design and metric calculation. Confirm the planning authority separately, including any National Park jurisdiction.
How do BNG exemptions work for a small Portsmouth development?
Since 6 August 2026, a red-line site of 0.2 hectares or less may qualify for exemption if the statutory conditions are satisfied, including no adverse effect on onsite priority habitat. Other ecological duties may remain.
How can habitat retention help with BNG in Portsmouth?
Retain valuable habitats and connections where feasible, and test how the layout affects them. If a genuine shortfall remains, use the applicable gain hierarchy and habitat trading rules to select a suitable delivery route.
When is the final gain plan needed in Portsmouth?
For eligible ordinary applications the final statutory Biodiversity Gain Plan normally needs approval after planning permission and before commencement. Check what the council asks for during validation and whether a management plan is needed.
Talk to ACP / Site enquiries
What does your site need next?
Tell us where the site is, what you plan to build and how far the application has progressed. We’ll use that context to discuss the surveys, calculations or plans your project needs.
What to have to handA red-line plan, an existing ecology report or a request from the council can help us scope the work. Start with whatever you already have.
Request a site-specific quotation
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Portsmouth BNG
Sources and references
Reviewed 10 November 2026.
Official planning and nature recovery sources
- Current GOV.UK exemption guidance
- View the official local nature recovery materials
- Appropriate assessment guidance
- Adopted Portsmouth Plan 2012
- Portsmouth Biodiversity Background Paper
- Portsmouth 2040 Local Plan examination
- Latest Portsmouth 2040 examination news
- Future Portsmouth Plan 2045
- Portsmouth Bird Aware Solent contribution rates
- GOV.UK's BNG guidance
- statutory biodiversity metric downloads
- National Planning Policy Framework: biodiversity policies N1 and N2