| Bledi Services Ltd | Administrative & support | 2018 |
| Blesk Cleaning Services Ltd | Administrative & support | 2021 |
| Bless One Ltd | Wholesale & retail | 2014 |
| Blessed Winners Ltd | Wholesale & retail | 2026 |
| Blessings Abound Ltd | Wholesale & retail | 2025 |
| Bletchley Investments Ltd | Real estate | 2022 |
| Blinkdrivex Ltd | Information & communication | 2019 |
| Bliss Services London Limited | Wholesale & retail | 2025 |
| Blissful Blooms Limited | Health & social care | 2024 |
| Blkkk Panda Ltd | Construction | 2026 |
| BLM Ogistics Limited | Transport & logistics | 2025 |
| Blockbase Ltd | Construction | 2024 |
| Bloomandberries Ltd | Hospitality | 2026 |
| Bloomsbury Court Management Company Limited | Households | 1981 |
| Blossom Fashion Limited | Wholesale & retail | 2018 |
| BLU & Penk Ltd | Wholesale & retail | 2024 |
| BLU Smokes Ltd | Wholesale & retail | 2023 |
| Blue Cactus Services Ltd | Real estate | 2020 |
| Blue Canyon Properties Ltd | Real estate | 2024 |
| Blue Eyes Trading L L Limited | Wholesale & retail | 2026 |
| Blue Eyes Trading Ltd | Wholesale & retail | 2025 |
| Blue Force Limited | Administrative & support | 2022 |
| Blue Heaven Enterprises Limited | Real estate | 2012 |
| Blue Horse London Limited | Wholesale & retail | 2021 |
| Blue Iris Day Nursery Ltd | Education | 2015 |
| Blue Planet Technologies Ltd | Information & communication | 2021 |
| Blue Pluming Ltd | Construction | 2015 |
| Blue Sapphire Investments Limited | Real estate | 2015 |
| Blue Sky J5 Ltd | Transport & logistics | 2019 |
| Blue Star Builders Ltd | Wholesale & retail | 2024 |
| Blue Star Property Investments Ltd | Real estate | 2025 |
| Blue Star Windows Ltd | Wholesale & retail | 2022 |
| Blue Summit Technologies Ltd | Information & communication | 2021 |
| Blue Valeting Ltd | Other services | 2019 |
| Bluebell Renewable Energy Ltd | Professional & scientific | 2019 |
| Blueberry Investment Properties Ltd | Real estate | 2024 |
| Bluehawk Automotive Limited | Wholesale & retail | 2023 |
| Blueoak Care Ltd | Health & social care | 2025 |
| Bluepeaks Traders Ltd | Wholesale & retail | 2025 |
| Bluesprings Ltd | Administrative & support | 2023 |
| Bluestar Cleaning Services Ltd | Administrative & support | 2016 |
| Bluestar Motors Ltd | Transport & logistics | 2023 |
| Bluestone Deep Limited | Real estate | 2019 |
| Blufin Advisors Ltd | Professional & scientific | 2015 |
| BM Clicks Ltd | Professional & scientific | 2025 |
| BM Consultings Limited | Information & communication | 2007 |
| Bmaa Services Ltd | Information & communication | 2018 |
| BN1 UK Properties Ltd | Real estate | 2026 |
| Bnait Enterprise Ltd | Real estate | 2024 |
| BNL Body Nutrition Labs Ltd | Wholesale & retail | 2021 |
| BNS Company (Property Holdings) Limited | Water & waste | 2000 |
| BNS Construction Services Ltd | Construction | 2024 |
| BNZ Computers Ltd | Wholesale & retail | 2020 |
| BOB Building Construction Ltd | Construction | 2019 |
| Bobbi Properties Ltd | Real estate | 2020 |
| Bobbys Convenience Ltd | Wholesale & retail | 2022 |
| Bobytiling Ltd | Construction | 2025 |
| BOD Nutrition Ltd | Manufacturing | 2025 |
| Body Blitz Ltd | Arts & recreation | 2025 |
| Boilers London Pro Ltd | Construction | 2025 |
| Boked Builders Limited | Construction | 2008 |
| Bombay Emporium (UK) Limited | Wholesale & retail | 2011 |
| Bombay Restaurant Limited | Hospitality | 2026 |
| BON Mackenzie Limited | Real estate | 2021 |
| Bond Street Food and Wine Ltd | Wholesale & retail | 2026 |
| Bonsai Motion Pictures Limited | Information & communication | 2020 |
| Bonsai Property Developers Ltd | Administrative & support | 2025 |
| Book Publishing House Ltd | Wholesale & retail | 2025 |
| Book UNI Limited | Education | 2019 |
| Bookbliss Limited | Professional & scientific | 2024 |
| Booker Aircraft Leasing Limited | Administrative & support | 2011 |
| Booker UK Investments Limited | Financial services | 2011 |
| Booking Helps Ltd | Administrative & support | 2023 |
| Books & Periodicals Agency Limited | Information & communication | 2005 |
| Boon Music Ltd | Information & communication | 2021 |
| Boora Transport & Logistics Ltd | Transport & logistics | 2025 |
| Booze in Town Ltd | Wholesale & retail | 2024 |
| Bossa Balloons Limited | Manufacturing | 2026 |
| Boundtrace Limited | Professional & scientific | 1998 |
| Boutique Developments (UK) Ltd | Real estate | 2012 |
| Bowman Rentals Limited | Real estate | 2020 |
| BOX7 Ltd | Wholesale & retail | 2023 |
| Boyke Security Ltd | Administrative & support | 2019 |
| Boyku Technology Limited | Wholesale & retail | 2016 |
| BP Brothers Ltd | Hospitality | 2025 |
| BPH Data Limited | Information & communication | 1992 |
| Bpssuns Law Chambers Ltd | Professional & scientific | 2025 |
| Braidsbymm Limited | Other services | 2024 |
| Brainpowers UK Ltd | Financial services | 2022 |
| Branch Alnaqeeb Pioneer Food Industries Limited | Other services | 2019 |
| Brand Fitted Kitchens & Wardrobes Limited | Construction | 2024 |
| Brand New Worlds Ltd | Professional & scientific | 2025 |
| Brand Talks Limited | Wholesale & retail | 2022 |
| Brandtree Limited | Information & communication | 2026 |
| Brar Brickwork Ltd | Construction | 2023 |
| Brar Properties Development Limited | Real estate | 2018 |
| Brar Reading Properties Limited | Real estate | 2024 |
| Brass & Brick Ltd | Real estate | 2025 |
| Brass Fittings Ltd | Wholesale & retail | 2025 |
| Bravo World Food Imports Ltd | Manufacturing | 2019 |