| Birch Tree Bloodstock Limited | Bedale | 2023 |
| Birch Tree Care (South East) Ltd | Ramsgate | 2019 |
| Birch Tree Projects Limited | Long Sutton , Spalding | 2021 |
| Birch Utility Services Limited | Exeter | 2009 |
| Birch View Farm Limited | Bewdley | 2014 |
| Birch's Farms Limited | Cambridge | 2024 |
| Birchams Wood Ltd | Gloucester | 2022 |
| Birchanger Hall Farms Limited | Royston | 1996 |
| Birches Head GET Growing CIC | Stoke-On-Trent | 2023 |
| Birchfield Springs Limited | Kettering | 2010 |
| Birchland Properties Limited | Bath | 1963 |
| Birchlands Livery Yard Ltd | Romsey | 2003 |
| Birchpiece Farms Limited | West Sussex | 1966 |
| Birchwood Contracts Ltd | Colchester | 2019 |
| Birchwood Farms Limited | Carlisle | 1995 |
| Birchwood Forestry Hereford Ltd | Hereford | 2025 |
| Bird and Pest Solutions Ltd | Bristol | 2009 |
| Birdcombe Farm,Limited | Whitland Dyfed | 1946 |
| Birdland Conservation International Ltd | Coventry | 2011 |
| Birdlymes Farm Ltd | Chippenham | 2014 |
| Birds Bistro Enterprises Limited | Penrith | 2012 |
| Birds Country Products Ltd | Barnstaple | 2019 |
| Birds Hill Farms Ltd | Carlisle | 2023 |
| Birdsall Estates Company Limited | Malton | 1928 |
| Birdsall Farms Limited | Pontefract | 1997 |
| Birdston Estates Limited | Glasgow | 2001 |
| Birdstone Limited | Faringdon | 1977 |
| Birkhill Farm Equestrian Centre Limited | Bradford | 2009 |
| Birnie & Stewart Ltd | Aberdeen | 2015 |
| Birse Trading Company Limited | Banchory | 2007 |
| Birstwith Barkyard Ltd | Harrogate | 2025 |
| Birthtree Limited | Edinburgh | 2020 |
| Bisel Limited | Lincoln | 2005 |
| Bishop Auckland and District Angling Club | Crook | 1996 |
| Bishop Auckland Farriers Limited | Bishop Auckland | 2014 |
| Bishop Court Farm Limited | Harrow | 2020 |
| Bishopdale Sporting Club Ltd | York | 2026 |
| Bishops Green Farm Limited | Newbury | 2017 |
| Bishopscourt Farms Ltd | Dromore | 2011 |
| Bishopswood Freehold Limited | Walton On Thames | 2024 |
| Bishopton Company Limited | Kirkcudbright | 2019 |
| Bishopwearmouth Co-Operative Community Interest Company | Sunderland | 2010 |
| Bishton Farm Pools Limited | Stafford | 2018 |
| Bisley Birds Ltd | Stroud | 2025 |
| Bisley Partners Ltd | Burgess Hill | 2007 |
| Bisley Trees Limited | London | 2020 |
| Bison Eco Limited | Bath | 2024 |
| Bissell Wood Estate Limited | Birmingham | 2011 |
| Bisterne Farms | Bournemouth | 1980 |
| Bithia Limited | Cambridge | 2010 |
| Bittadon Farms Limited | Barnstaple | 2004 |
| Bittescombe Manor Estate Ltd | Taunton | 2017 |
| Bitteswell Farms Limited | Lynch Wood, Peterborough | 2018 |
| BJ & R Foord Limited | Oxfordshire | 2003 |
| BJ Holdings Ltd | Swansea | 2010 |
| BJ Unwin Forestry Consultancy Ltd | Greater Manchester | 2019 |
| BJA Services Limited | Tonbridge | 2007 |
| BJC Construction Limited | Lincoln | 2019 |
| BJC Farm & Equine Ltd | Wimborne | 2024 |
| Bjc-Uk (Estates) Ltd | Carmarthen | 2011 |
| BJH Tree and Grounds Maintenance Ltd | Exeter | 2018 |
| BJS Farms Ltd | Bishop Auckland | 2010 |
| Bjss Environmental Limited | London | 2021 |
| BJT Land Holdings Limited | Stourbridge | 2011 |
| BK Bloodstock Ltd | Burton-On-Trent | 2024 |
| BKB Tree & Hedge Surgery Limited | Cupar | 2026 |
| BKK Equestrian Ltd | York | 2025 |
| BKR Farming Limited | Londonderry | 2021 |
| BLA Shipping Ltd | Hull | 2024 |
| Black & White Technologies Ltd | Brackley | 2007 |
| Black ADA Limited | Dudley | 2002 |
| Black Agricultural Contracting Limited | Thetford | 1995 |
| Black Barn Farm Limited | Winchester | 2022 |
| Black BEE Farmers Ltd | London | 2025 |
| Black Bourn Vineyards Limited | Bury St. Edmunds | 2020 |
| Black Cherry Alpacas Ltd | York | 2023 |
| Black Contracts Ltd | Cookstown | 2004 |
| Black Corries Estate Management Limited | Dunfermline | 2010 |
| Black Dog Agri Engineering Ltd | Dumfries | 2025 |
| Black Dog Charcoal Ltd | Horsham | 2021 |
| Black Dog Firewood Limited | Horsham | 2021 |
| Black Dog Forestry & Arboriculture Limited | Horsham | 2021 |
| Black Dog Forestry Limited | Horsham | 2018 |
| Black Dog Honey Bees Ltd | Plymouth | 2020 |
| Black Dog Pest Solutions UK Limited | West Bromwich | 2022 |
| Black Dragon Investments Ltd | London | 2018 |
| Black Eagle Development and Project Managment Corporation Ltd | London | 2025 |
| Black Environmental Services Limited | Tayport | 2002 |
| Black Forest Forest & Garden Ltd | Pontypridd | 2015 |
| Black Gold Alpacas Ltd | Ledbury | 2022 |
| Black Grove Farm Ltd | Ware | 2018 |
| Black Grove Greens CIC | Ware | 2018 |
| Black Growth CIC | London | 2022 |
| Black Hill Shropshire Limited | Bucknell | 2020 |
| Black Horse Healthcare Limited | Chesterfield | 2020 |
| Black Horses Ltd | Grange Over Sands | 2005 |
| Black Isle Timber Harvesting Limited | Rosemarkie | 2018 |
| Black Isle Yurts Limited | Inverness | 2013 |
| Black Mountain Biomass Ltd | London | 2023 |
| Black Mountain Forestry Ltd | Brecon | 2018 |