Planning Conditions for Biodiversity Net Gain

Biodiversity Net Gain Conditions Set by Local Planning Authorities

All over England, local planning authorities are tasked with enforcing biodiversity net gain (BNG) throughout the planning process any time it applies to specific development proposals. Lots of new developments are subject to the mandatory requirement, aside from certain exemptions, such as any householder application, development within the de minimis threshold, project for the transport network, or self-build and custom-build development with less than 9 dwellings and a total site area no larger than 0.5 hectares

Other than that, many commercial developments, residential developments and nationally significant infrastructure projects would be subject to the biodiversity gain requirements since it became mandatory on 12 February 2024, with a small sites metric released for smaller developments on 2 April 2024. The BNG objective insists that developers must ensure that the activities carried out on the development site leave the natural environment in a measurably better state, deliver at least 10% biodiversity net gain, and see it secured for at least 30 years.

Reinforced by legislation – including Schedule 14 of the Environment Act 2021 and Schedule 7A of the Town and Country Planning Act 1990 – all applicable developments must provide evidence that they can deliver biodiversity net gain (BNG). The LPA requirements of the relevant local planning authority, however, can add further potential planning obligations, especially if local nature recovery strategies, local development orders, and existing local policies apply.

It can be difficult enough to meet biodiversity net gain requirements without seeing further local policy apply based on the location, circumstances or habitats present in conjunction with the development. As experts in mandatory BNG, Arbtech outlines the potential planning conditions that could complicate the planning application process and what local authorities they apply to.

BNG Requirements from a Local Authority

All local planning authorities in England must enforce the legal requirement. On top of that, however, they can integrate additional stipulations as part of the pre-commencement condition. LPAs can choose to do this for a number of reasons, but it’s often because they want to further increase biodiversity in the area, speed up the process of initiating biodiversity enhancements, avoid impacts caused by development projects, or prevent unnecessary adverse effects on the environment.

An easy method to support biodiversity and create a more significant increase is through insisting on a higher percentage from applicable developers above the usual 10% net gain. More and more local authorities are requesting a larger net gain in biodiversity, often moving up to 20% but sometimes even going as high as 30%. It could make it more difficult to deliver BNG, but if the developer cannot achieve 10% on-site gains, off-site gains from land outside the site is still an option.

If it isn’t possible to see the biodiversity gain objective achieved on-site, developers will be forced to buy statutory biodiversity credits and/or off-site biodiversity units. At that point, the process will at least benefit the local environment. Other methods of getting more out of the planning policy and expecting more from the legal agreement include putting firmer restrictions in place to protect irreplaceable habitat areas and protected sites or setting more parameters at the biodiversity gain condition stage for developers to achieve before being granted planning permission.

LPAs Enforcing 20% Net Gain or Other BNG Conditions

In the section below, we’ve detailed the local authorities enforcing a higher net gain percentage and other caveats. We’ve also listed all of the statutory protected sites across England that could force LPAs to be more stringent when it comes to planning decisions, such as Sites of Special Scientific Interest (SSSI), Special Areas of Conservation (SAC), Marine Conservation Zones (MCZs) and National Nature Reserves (NNRs).

Further Net Gain Increase

Currently Enforcing 20%

• Guildford Borough Council

Currently Considering Enforcing 20%

Currently Enforcing 20% Under Specific Conditions

• Brighton & Hove City Council
• Cherwell District Council
• Mid Sussex District Council
• Richard upon Thames Council
• Sheffield City Council
• West Oxfordshire District Council
• Worthing Borough Council

Currently Considering Enforcing 11-25%

• South Oxfordshire District Council
• Vale of Shite Horse District Council

Currently Considering Enforcing 30%

• Kingston Council
• Tower Hamlets Council

Important Habitat Areas

Sites of Special Scientific Interest (SSSI)

Location	Biological Sites	Geological Sites	Both	Total
Cumbria	170	70	38	278
North Yorkshire	162	56	23	241
Devon	109	71	31	211
Cornwall	81	54	32	167
Norfolk	123	25	15	163
Suffolk	109	28	5	139
Dorset	103	20	16	134
Wiltshire	108	21	5	127
Somerset	83	35	9	121
Gloucestershire	69	32	20	121
Lincolnshire	98	23	3	121
Worcestershire	106	15	5	118
Hampshire	108	4	6	114
Northumberland	N/A	N/A	N/A	110
Oxfordshire	76	27	7	110
Shropshire	N/A	N/A	N/A	101
Cambridgeshire	90	10	1	101
Derbyshire	54	28	17	99
Kent	67	21	10	98
County Durham	67	16	5	88
Avon	38	39	9	86
Essex	64	19	3	86
Herefordshire	62	21	4	83
West Sussex	54	19	5	78
Leicestershire	58	12	6	76
Berkshire	63	8	0	71
Lancashire	49	14	6	69
Nottinghamshire	63	1	2	66
Buckinghamshire	55	10	0	65
Staffordshire	N/A	N/A	N/A	65
East Sussex	46	14	4	64
Cheshire	51	7	5	63
Surrey	52	8	2	62
Warwickshire	N/A	N/A	N/A	62
Northamptonshire	48	9	0	57
East Riding of Yorkshire	39	14	3	50
Hertfordshire	36	7	0	43
Isle of Wight	26	4	11	41
Bedfordshire	35	5	0	40
Greater London	30	7	0	37
Tyne and Wear	25	6	6	37
South Yorkshire	18	14	3	35
West Yorkshire	21	9	2	32
West Midlands	11	9	3	23
Greater Manchester	14	5	2	21
Rutland	16	1	2	19
Cleveland	12	4	2	18
Merseyside	10	1	3	14

Special Areas of Conservation (SAC)

Location	Areas	Total
South West England	Braunton Burrows, Culm Grasslands, Dartmoor, Exmoor Heaths, The Isles of Scilly Complex, River Camel	6
East of England	Breckland, Essex Estuaries, The Norfolk Valley Fens, Ouse Wahes, The Wash and North Norfolk Coast	5
North East England	Durham Coast, North Pennine Moors, North York Moors, River Derwent, River Tweed	5
North West England	Duddon Mosses, Lake District High Fells, Morecambe Bay, River Eden, Solway Firth	5
South East England	Ashdown Forest, Chilterns Beechwoods, Dorset Heaths, River Itchen, The Solent Maritime	5
West Midlands and Central England	Cannon Chase, Fenn’s, Whixall, Bettisfield, Wem and Cadney Mosses, River Mease	3

Marine Conservation Zones (MCZs)

Region	Involved Counties	Zones	Total
South West England	Cornwall, Devon, Somerset	Camel Estuary, Dart Estuary, Erme Estuary, Helford Estuary, Morte Platform, South of the Isles of Scilly, South West approaches to the Bristol Channel	7
North West England	Cumbria, Lancashire	Allonby Bay, Cumbria Coast, Fylde, Ribble Estuary, Solway Firth, Wyre-Lune	6
South East England	Dorset, Hampshire, Isle of Wight, Kent, Sussex	Beachy Head West, Chesil Beach and Stennis Ledges, Folkestone Pomerania, Goodwin Sands, Kingmere, The Needles	6
North East England	Yorkshire, Northumberland	Berwick to St Mary’s, Coquet to St Mary’s, Holderness Inshore, North East of Farnes Deep, Runswick Bay	5
East of England	Essex, Norfolk, Suffolk	Blackwater, Crouch, Road and Colne Estuaries, Cromer Shoal Chalk Beds, Orford Inshore, Swallow Sand	4
Offshore Regions	N/A	The Canyons, Cape Bank, East of Haig Fras, South West Deeps (East), South West Deeps (West)	5

National Nature Reserves (NNRs)

Location	Reserves	Total
Cumbria	Bassenthwaite Lake, Blelham Bog, Clawthorpe Fell, Cliburn Moss, Drumburgh Moss, Duddon Mosses, Finglandrigg Woods, Gowk Bank, Great Asby Scar, Hallsenna Moor, High Leys, Moor House-Upper Teesdale, North Fen, North Walney, Park Wood, Roudsea Wood & Mosses, Rusland Moss, Sandscale Haws, Sandybeck Meadow, Smardale Gill, South Solway Mosses, Tarn Moss, Thornhill Moss and Meadows, Walton Moss, Whitbarrow	25
Norfolk	Ant Broads and Marshes, Blakeney Point, Brettenham Heath, Bure Marshes, Calthorpe Broad, Dersingham Bog, Foxley Wood, Heigham Holmes, Hickling Broad, Holkham, Holme Dunes, Ludham – Potter Heigham Marshes, Martham Broad, Mid-Yare, Redgrave and Lopham Fen, Roydon Common, Scolt Head Island, Swanton Novers, The Wash, Weeting Heath, Wintering Dunes	21
Somerset	Barrington Hill Meadows, Bridgwater Bay, Dunkery & Horner Woods, Ebbor Gorge, Ham Wall, Hardington Moor, Hawkcombe Woods, Huntspill River, Rodney Stoke, Shapwick Heath, Somerset Levels, Tarr Steps Woodland, Westhay Moor	13
Dorset	Arne Reedbeds, Durlston, Hambledon Hill, Hartland Moor, Hog Cliff, Holt Heath, Holton Heath, Horn Park Quarry, Mordon Bog, Stoborough Heath, Studland and Godlingston Heath, Valley of Stones	12
Kent	East Blean Woods and Church Woods, Dungeness, Elmley, Ham Street Woods, High Halstow, Lydden Temple Ewell, Sandwich and Pegwell Bay, Stodmarsh, Swanscombe Skull Site, The Swale, Wye	11
Hampshire	Ashford Hangers, Ashford Hill, Beacon Hill, Butser Hill, Castle Bottom, Kingston Great Common, Martin Down, North Solent, Old Winchester Hill, Titchfield Haven	10
Cambridgeshire	Barnack Hills & Holes, Bedford Purlieus, Castor Hanglands, Chippenham Fen, Holme Fen, Monks Wood, Upwood Meadows, Wicken Fed, Woodwalton Fen	9
Devon	Axmouth to Lyme Regis Undercliffs, Berry Head – Sharkham Point, Black-a-Tor Copse, Dawlish Warren, Dendles Wood, Dunsdon Farm, East Dartmoor Woods and Heaths, Slaptop Ley, Wistman’s Wood	9
North Yorkshire	Acaster South Ings, Duncombe Park, Forge Valley Woods, Ingleborough, Ling Gill, Malham Tarn, New House Farm, Scoska Wood, Skipwith Common	9
Northumberland	Derwent Gorge & Muggleswick Woods, Farne Islands, Greenlee Lough, Kielder Mires, Kielderhead, Lindisfarne, Muckle Moss, Newham Bog, Whitelee Moor	9
Suffolk	Benacre, Bradfield Woods, Cavenham Heath, Orfordness-Havergate, Redgrave and Lopham Fen, Suffolk Coast, Thetford Heath, Westleton Heath	8
Essex	Blackwater Estuary, Colne Estuary, Dengie, Hales Wood, Hamford Water, Hatfield Forest, Leigh	7
Lincolnshire	Bardney Limewoods, Far Ings, Gibraltar Point, The Wash, Lincolnshire Coronation Coast, Saltfleetby-Theddlethorpe Dunes, Donna Nook	7
Wiltshire	Fyfield Down, Langley Wood, North Meadow, Parsonage Down, Pewsey Downs, Prescombe Down, Wylye Down	7
County Durham	Cassop Vale, Castle Eden Dene, Derwent Gorge & Muggleswick Woods, Durham Coast, Moor House-Upper Teesdale, Thrislington	6
Derbyshire	Calke Park, Derbyshire Dales, Dovedail, Kinder Scout	4
East Sussex	Castle Hill, Lewes Downs (Mounth Caburn), Lullington Heath, Pevensey Levels	4
Gloucestershire	Cotswold Commons & Beechwoods, Highbury Wood, Lady Park Wood, The Hudnalls	4
Leicestershire	Bradgate Park, Charnwood Lodge, Cribb’s Meadow, Muston Meadows	4
Oxfordshire	Aston Rowant, Chimney Meadow, Cothill, Wychwood	4
Staffordshire	Aqualate Mere, Chartley Cross, Hulme Quarry, Mottey Meadows	4
Worcestershire	Bredon Hill, Chaddesley Woods, Foster’s Green Meadows, Wyre Forest	4
Bedfordshire	Barton Hills, King’s Wood (Heath & Reach), Knocking Hoe	3
Cornwall	Golitha Falls, Goss Moore, The Lizard	3
Herefordshire	Downton Gorge, Moccas Park, The Flits	3
London	Richmond Park, Ruislip Woods, South London Downs	3
Merseyside	Ainsdale Sand Dunes, Cabin Hill, Ribble Estuary	3
Shropshire	Fenn’s, Whixall and Bettisfield Mosses, Stiperstones, Wem Moss	3
Surrey	Ashtead Common, Chobham Common, Thursley	3
Avon	Gordano Valley, Leigh Woods	2
Cheshire	Rostherne Mere, Wybunbury Moss	2
East Riding of Yorkshire	Lower Derwent Valley, Spurn	2
Lincolnshire	Gait Barrows, Ribble Estuary	2
Northamptonshire	Buckingham Thick Copse, Collyweston Great Wood & Easton Hornstocks	2
West Midlands	Sutton Park, Wren’s Nest	2
West Sussex	Ebernoe Common, Kinglsey Vale	2
Berkshire	Chobham Common	1
Buckinghamshire	Burnham Beeches	1
Cleveland	Teesmouth	1
Hertfordshire	Broxbourne Woods	1
Isle of Wight	Newtown	1
Nottinghamshire	Sherwood Forest	1
South Yorkshire	Humberhead Peatlands	1

Other Policies and Requirements

Specific Validation Requirements

• Mansfield District Council

Additional Ecological Surveys

• Lincolnshire County Council

Meet the BNG Requirements in Your Location

In a development that applies to mandatory biodiversity net gain, any factor that could have adverse impacts on the planning application stage, any priority habitat present, and the process of securing BNG will affect how a planning application will be submitted and approved.

Between meeting the planning policy of your local authority to dealing with other matters based on the circumstances of your site and project, you need sufficient guidance to ensure compliance and operate within good practice guidelines.

For example, you may need to generate habitat creation, initiate habitat enhancement, navigate the mitigation hierarchy, account for existing habitat lost and work with section 106 agreements and conservation covenants if off-site biodiversity gains from professionals who own land in order to ensure that the planning proposals meet planning laws.

Speak to Arbtech About Local BNG Conditions

Our team can help you with whatever you need to achieve BNG within the red-line boundary of your site. If the statutory biodiversity metric calculation tool indicates that off-site units are needed, we can also help with that. Additionally, we are able to help with completing a biodiversity gain plan document and can undertake a habitat management and monitoring plan (HMMP) for long-term maintenance and ongoing management of efforts to enhance biodiversity.

With our help, you can see BNG apply to your development just as it’s meant to, all while seeing planning permissions granted. Reach out to our team by calling us, emailing us or filling out a quote form on our contact page, and we will send you a free quote for the services you need. A local ecological consultant with knowledge of your local planning authority and their unique requirements will then be able to estimate a pre-development biodiversity value and a post-development biodiversity value, compare them, and work out what’s needed to hit the biodiversity gain objective.