| Bimson Trustees Limited | Administrative & support | 2024 |
| Binderholz UK Group Limited | Financial services | 2019 |
| Bingham Yates Limited | Construction | 2012 |
| Binnings of Cumbria Limited | Extraterritorial | 2002 |
| Binsey Limited | Professional & scientific | 2019 |
| Biocell Agri Limited | Agriculture & fishing | 2003 |
| Biogest UK Ltd | Water & waste | 2013 |
| Birch House Properties Ltd | Real estate | 2026 |
| Birchwood Farms Limited | Agriculture & fishing | 1995 |
| Bird Nest Ltd | Hospitality | 2024 |
| Birds Hill Farms Ltd | Agriculture & fishing | 2023 |
| Birkbeck Commercials Limited | Manufacturing | 2016 |
| Birkbeck Gardens (Kirkby Stephen) Management Company Limited | Real estate | 2012 |
| Birley Steele Lightfoot Ltd | Professional & scientific | 2009 |
| Bison Cove Ltd | Professional & scientific | 2016 |
| Bitline Limited | Construction | 1988 |
| Biz-Lytics Limited | Information & communication | 2018 |
| Bjdvd Ltd | Information & communication | 2013 |
| BJH Energy Ltd | Construction | 2022 |
| BJS Logistics Ltd | Transport & logistics | 2021 |
| Black Box Architects Limited | Professional & scientific | 2005 |
| Black Box Security Solutions Ltd | Construction | 2013 |
| Black Magic Car Detailers Limited | Administrative & support | 2019 |
| Black Rock Dive Centre UK Limited | Arts & recreation | 2014 |
| Black Rock Services Limited | Administrative & support | 2007 |
| Blackdyke Engineers Limited | Manufacturing | 1966 |
| Blackfriars Tattoo House Limited | Administrative & support | 2015 |
| Blackgold Data Services Ltd | Other services | 2008 |
| Blacklock Harvesting Ltd | Agriculture & fishing | 2009 |
| Blackstone Research and Development Limited | Information & communication | 2010 |
| Blackthorn International Limited | Wholesale & retail | 2012 |
| Blackthorn Property Enterprises Ltd | Construction | 2024 |
| Blasc Limited | Wholesale & retail | 2010 |
| Blast Clean North West Limited | Wholesale & retail | 2003 |
| Blay Holdings Ltd | Real estate | 2026 |
| Blazar Logic Ltd | Information & communication | 2025 |
| Bleaberry S G Company Limited | Agriculture & fishing | 2010 |
| Bleaberry Sporting GUN Company Limited | Administrative & support | 2014 |
| Bleasdale & Co. Solicitors Limited | Professional & scientific | 2016 |
| Blencowe Lime Co.,Limited(The) | Extraterritorial | 1936 |
| Blencowe Street Management Company Ltd | Households | 2017 |
| Blenders Barber Ltd | Other services | 2023 |
| Blenders Barbers 54 Ltd | Other services | 2026 |
| Blenheim Lodge Limited | Hospitality | 2005 |
| Bliss Hair & Tanning Limited | Other services | 2026 |
| Blokk Concepts Limited | Extraterritorial | 2017 |
| Blonde D'Aquitaine Breeders Society of Great Britain Limited(The) | Other services | 1971 |
| Bloodline Solutions Limited | Information & communication | 2026 |
| Blossomdale Developments Ltd | Construction | 2020 |
| Blue Empowering Media Ltd | Professional & scientific | 2025 |
| Blue Key Property Developments Limited | Construction | 2021 |
| Blue Rock UK Holdings Limited | Professional & scientific | 2021 |
| Blue SIX Consultants Limited | Professional & scientific | 2014 |
| Blue Thread Works Ltd | Administrative & support | 2025 |
| Bluebell Meadows (Cumwhinton) Management Company Limited | Households | 2020 |
| Bluefield Limited | Administrative & support | 2002 |
| Bluestone Premier Solutions Limited | Real estate | 2025 |
| Bluezon Limited | Manufacturing | 2008 |
| Bmch Construction Ltd | Construction | 2019 |
| Bmpt Academy Ltd | Education | 2020 |
| Bmpt LLP | | 2022 |
| Boardway Tree and Ground Care Limited | Administrative & support | 2025 |
| BOB Lancaster & SON Limited | Construction | 2014 |
| Bodytek Limited | Arts & recreation | 2007 |
| Boleside Investments Limited | Real estate | 2009 |
| Bollman Headwear Europe Limited | Wholesale & retail | 2001 |
| Bollywood Thread Brow & Beauty Ltd | Other services | 2015 |
| Bolton's Dairy Ltd | Agriculture & fishing | 2022 |
| Bomas Lifting Ltd | Administrative & support | 2025 |
| Bonnie LAD Logistics Ltd | Transport & logistics | 2022 |
| Boomalli Property Ltd | Real estate | 2025 |
| Bordaloo Limited | Water & waste | 2025 |
| Border Aggregates and Landscaping Supplies Limited | Transport & logistics | 2003 |
| Border Barrier Systems Limited | Extraterritorial | 2021 |
| Border Beats Ltd | Arts & recreation | 2018 |
| Border Cabs (2000) Limited | | 1999 |
| Border Catering Ltd | Hospitality | 2025 |
| Border City Autos 20 Limited | Wholesale & retail | 2020 |
| Border City Cards Ltd | Wholesale & retail | 2025 |
| Border City Developments (Cumbria) Ltd | Real estate | 2025 |
| Border City Glass Ltd | Manufacturing | 2013 |
| Border City Properties Ltd | Real estate | 2023 |
| Border City Scaffolding Limited | Construction | 2015 |
| Border City Vending Ltd | Administrative & support | 2024 |
| Border COD Limited | Hospitality | 2012 |
| Border Counties Farming Limited | Professional & scientific | 1981 |
| Border Developments (Carlisle) Ltd | Construction | 2022 |
| Border Developments (Cumbria) Limited | Construction | 2008 |
| Border E-Bikes Limited | Wholesale & retail | 2021 |
| Border ESK Fencing Limited | Manufacturing | 2004 |
| Border Fire and Security Limited | Wholesale & retail | 1985 |
| Border Floor Limited | Construction | 2011 |
| Border Food Machinery Limited | Wholesale & retail | 2001 |
| Border Gifts Limited | Wholesale & retail | 2023 |
| Border Group Limited | Administrative & support | 2020 |
| Border Heritage Limited | Information & communication | 1997 |
| Border I.P. Limited | Real estate | 2014 |
| Border Investments Ltd | Financial services | 2013 |
| Border IP Two Limited | Extraterritorial | 2016 |
| Border Logging Limited | Transport & logistics | 2014 |