| Bowmans Cross Ltd | Real estate | 2018 |
| Bowmans Farms Limited | Administrative & support | 2001 |
| Box Enterprises Ltd | Other services | 2022 |
| Boxgrove House Association Limited | Professional & scientific | 2011 |
| Boxsmiths Limited | Manufacturing | 2019 |
| Bpmrj Limited | Real estate | 2019 |
| Bpof III Tamac Partners LLP | | 2014 |
| Bpof III Tamac Partnership Management Limited | Professional & scientific | 2014 |
| BR Creative Ltd | Information & communication | 2023 |
| BR Jones and Sons Ltd | Construction | 2022 |
| Bradbourne Property Finders Limited | Real estate | 2017 |
| Bradley Hare Inn Ltd | Hospitality | 2025 |
| Bradley Jones Associates Limited | Professional & scientific | 2016 |
| Brambles Outdoor Nursery Group Limited | Education | 2019 |
| Bramblewood (Old Basing) Residents Management Company Limited | Households | 1999 |
| Bramley Court Basingstoke Management Limited | Households | 2009 |
| Bramlys Ltd | Wholesale & retail | 2018 |
| Brammall Holdings Limited | Financial services | 2017 |
| Brampton Gate Management Company Limited | Households | 2018 |
| Bramshaw Autos (Hampshire) Limited | Professional & scientific | 1965 |
| Bramshaw Leisure Ltd | Extraterritorial | 2015 |
| Brancaster Court Management Company Limited | Households | 1989 |
| Brand Development Ltd | Wholesale & retail | 2022 |
| Brandwork Studio Limited | Professional & scientific | 2019 |
| Brave Promotions Limited | Hospitality | 2016 |
| Braveheart K9 Training and Pet Services LLP | | 2025 |
| Bravo Alpha Limited | Administrative & support | 2025 |
| Bray Group Holdings Limited | Financial services | 2025 |
| Bray Restaurant Group Limited | Hospitality | 2025 |
| BREAK4HOLIDAYS Ltd | Administrative & support | 2013 |
| Breckenwood Limited | Real estate | 2000 |
| Bredy Veterinary Centre Limited | Professional & scientific | 2011 |
| Breen Sport Horses Limited | Arts & recreation | 2012 |
| Breeze Developments Limited | Construction | 2007 |
| Breeze Environmental Limited | Other services | 2016 |
| Breezy Homes Limited | Construction | 2025 |
| Brennan Farms Ltd | Agriculture & fishing | 1994 |
| Brent Works (Colindale) Management Company Limited | Households | 2010 |
| Brentford Lock West (Phase 1) Management Limited | Real estate | 2014 |
| Brentford Lock West (Phase 2) Management Limited | Households | 2017 |
| Brentford Lock West Estate Management Limited | Real estate | 2014 |
| Brera Life Sciences Consultancy Limited | Professional & scientific | 2014 |
| Brewgas (South) Limited | Extraterritorial | 2025 |
| Brian Daly Photography Limited | Professional & scientific | 2005 |
| Brian Franklin & SON Limited | Construction | 2014 |
| Brick House Conservation Ltd | Other services | 2022 |
| Brickfield Court Management Company Limited | Households | 2016 |
| Brickwood Construction & Developments Ltd | Construction | 2018 |
| Brickwood Land & Homes Ltd | Construction | 2026 |
| Bridge Farm Salisbury Limited | Agriculture & fishing | 2022 |
| Bridge Squared Limited | Administrative & support | 2009 |
| Bridgewater Pension Trustees Limited | Financial services | 1999 |
| Bridleway Grange Residents Management Company Limited | Households | 2022 |
| Briggs Property Holdings Ltd | Real estate | 2026 |
| Bright Farms Limited | Financial services | 2019 |
| Bright Feather Studios Limited | Information & communication | 2021 |
| Bright Heating & Plumbing Ltd | Construction | 2023 |
| Bright Horizon Travel Limited | Administrative & support | 2009 |
| Bright Letts Ltd | Real estate | 2021 |
| Bright Maize Limited | Agriculture & fishing | 2017 |
| Bright Seeds Limited | Wholesale & retail | 1988 |
| Bright Space Living Limited | Construction | 2025 |
| Bright Subsea Consulting Limited | Professional & scientific | 2024 |
| Bright Words Limited | Extraterritorial | 2017 |
| Brightech Construction Ltd | Construction | 2014 |
| Brighter Days Property (Wiltshire) Limited | Real estate | 2022 |
| Brighter Days Property Limited | Real estate | 2021 |
| Brighter Learning Academy Ltd | Education | 2014 |
| Brighter Learning Ltd | Education | 2015 |
| Brisfix Ltd | Manufacturing | 2020 |
| Brislington House Management Company Limited | Households | 2013 |
| Bristol Bling Ltd | Administrative & support | 2020 |
| Brit UK Holdings Ltd | Financial services | 2025 |
| Britannia Cutting Services Limited | Construction | 2002 |
| Britannia Mews (Great Harwood) Management Company Ltd | Households | 2022 |
| Britclear Limited | Transport & logistics | 2025 |
| Brittany Property Management Limited | Administrative & support | 2025 |
| Britz Fish and Chips Limited | Hospitality | 2019 |
| Brix and Bailey Limited | Manufacturing | 2013 |
| Brixham 28 Ltd | Real estate | 2017 |
| Broad Reach Communications Limited | Professional & scientific | 2010 |
| Broadband Wifi Ltd | Information & communication | 2003 |
| Broadfield (Facilities Management) Limited | Households | 2021 |
| Broadgate Management Limited | Professional & scientific | 2024 |
| Broadgate Residential Investments Ltd | Real estate | 2010 |
| Broadlands (Pudsey) Management Company Limited | Households | 2005 |
| Broadleaf Park (Rownhams) Management Company Limited | Households | 2020 |
| Broadoak Slow Limited | Agriculture & fishing | 2009 |
| Broadway Court (Wimbledon) Management Company Limited | Households | 2016 |
| Brock Property Holdings Limited | Financial services | 2021 |
| Brockaero Ltd | Professional & scientific | 2017 |
| Brockley Hot POD Yoga Ltd | Arts & recreation | 2022 |
| Brockway Ltd | Professional & scientific | 2019 |
| Brockwell Properties Limited | Construction | 2026 |
| Bromley Italian Food Ltd | Hospitality | 2022 |
| Bromspec Motorworks Limited | Wholesale & retail | 2012 |
| Brook Chase (Waterlooville) Management Company Limited | Households | 2017 |
| Brooklands (Chippenham) Management Company Limited | Real estate | 2008 |
| Brooklyn 4 X 4 Limited | Wholesale & retail | 1977 |
| Brooks Aeromobile Ltd | Professional & scientific | 2019 |