| Brompton Bicycle Limited | Manufacturing | 1976 |
| Brompton Bicycle Retail Limited | Wholesale & retail | 2023 |
| Brompton Bike Hire Ltd | Administrative & support | 2010 |
| Brookfield Court (Greenford) RTM Company Limited | Households | 2019 |
| Brooklyn Care Limited | Health & social care | 2013 |
| Brooklyn Health Limited | Health & social care | 2016 |
| Bros Property Investors Limited | Real estate | 2019 |
| Brosko Limited | Transport & logistics | 2024 |
| Brother Mechanics Ltd | Wholesale & retail | 2020 |
| Brothers Crescent Limited | Professional & scientific | 2012 |
| Brotherwood Joinery Limited | Construction | 2024 |
| Brownhill Chauffeurs Ltd | Transport & logistics | 2026 |
| Brownhill Group Limited | Transport & logistics | 2015 |
| Brunel Driving School Limited | Education | 2022 |
| Bruno Estate Limited | Real estate | 2025 |
| BST Property Holdings Limited | Financial services | 2025 |
| BT Double Glazing Limited | Construction | 2009 |
| Btelecom Limited | Information & communication | 2025 |
| BTM International UK Ltd | Wholesale & retail | 2000 |
| BTS Contracts Limited | Professional & scientific | 2021 |
| Btwl Perivale Limited | Wholesale & retail | 2024 |
| Bubble Properties Limited | Real estate | 1998 |
| Bubbles Bowls & Treats Ltd | Hospitality | 2026 |
| Buddiapp Ltd | Information & communication | 2026 |
| Budget Party Hire Ltd | Hospitality | 2019 |
| Budgetgems Ltd | Wholesale & retail | 2024 |
| Build & Decorate Ltd | Construction | 2016 |
| Build SL Ltd | Construction | 2023 |
| Builderberg Inc Ltd | Extraterritorial | 2011 |
| BUILDIT4U2 Ltd | Construction | 2026 |
| Buildom Limited | Construction | 2006 |
| Built by AMC Limited | Arts & recreation | 2024 |
| Bulco Limited | Administrative & support | 2017 |
| Bulldog Power Ltd | Wholesale & retail | 2012 |
| Bulls Team Limited | Professional & scientific | 2020 |
| BUN Brothers Ltd | Hospitality | 2025 |
| Bund Consulting Limited | Information & communication | 2022 |
| Bunk London Limited | Professional & scientific | 2018 |
| Buoyant Records Ltd | Information & communication | 2024 |
| Business Energy Consulting Ltd | Other services | 2023 |
| Busy Ltd | Construction | 2019 |
| Butt Partnership Limited | Real estate | 2020 |
| Butterfly Academy Limited | Education | 2022 |
| Butterfly Learning Limited | Education | 2017 |
| Butterfly Tuition Limited | Education | 2026 |
| Buttermilk London Limited | Wholesale & retail | 2021 |
| Buyot Limited | Health & social care | 2012 |
| Buzzmingle Media Ltd | Professional & scientific | 2024 |
| BVP IT Limited | Information & communication | 2015 |
| BW Courier Ltd | Transport & logistics | 2025 |
| BWA Motors Ltd | Wholesale & retail | 2025 |
| BWM Construction Ltd | Construction | 2023 |
| BX3 Property Ltd | Real estate | 2024 |
| BY Bhav Ltd | Professional & scientific | 2025 |
| By.U Inc Limited | Wholesale & retail | 2021 |
| BYS Ductwork Ltd | Construction | 2017 |
| C & a Business World PVT Ltd | Wholesale & retail | 2023 |
| C & E Electrical & Plumbing Limited | Wholesale & retail | 2005 |
| C and J Security Limited | Administrative & support | 2022 |
| C and Z Ross Property Ltd | Real estate | 2021 |
| C Harman Construction Ltd | Construction | 2015 |
| C P Sound Limited | Administrative & support | 1994 |
| C S Adventure Limited | Other services | 2014 |
| C&A Building Ltd | Other services | 2016 |
| C&C Construction Limited | Construction | 2024 |
| C&Gstore Ltd | Wholesale & retail | 2024 |
| C&L Bookkeeping Ltd | Construction | 2026 |
| C. J. O'Shea Construction Limited | Construction | 1980 |
| C. Ruane Limited | Professional & scientific | 2023 |
| C.A.S Build & Design Ltd | Construction | 2024 |
| C.Contractors Ltd | Manufacturing | 2025 |
| C.J. O'Shea Developments Limited | Construction | 1987 |
| C.L.A. Interiors Ltd | Construction | 2024 |
| C1 Whole Sellers Ltd | Wholesale & retail | 2023 |
| C2GO Ltd | Wholesale & retail | 2023 |
| CAB Management Solution Ltd | Information & communication | 2020 |
| CAB Management System Ltd | Information & communication | 2010 |
| Cablestream London Ltd | Administrative & support | 2016 |
| Caecus Construction Limited | Construction | 2022 |
| Caecus Group Holdings Limited | Financial services | 2023 |
| Caecus Group Lettings Limited | Real estate | 2023 |
| Caesar Plus Limited | Construction | 2025 |
| Cafe Twenty SIX Ltd | Hospitality | 2020 |
| Cairo One Limited | Wholesale & retail | 2024 |
| Cajetan Obinna Limited | Administrative & support | 2026 |
| Calcon Design Consultants Ltd | Professional & scientific | 2016 |
| Call to Scan Ltd | Health & social care | 2025 |
| Calumbridge Limited | Construction | 2016 |
| Camberwick Properties Limited | Real estate | 2002 |
| Cambria OIL Group & Partners Ltd | Wholesale & retail | 2003 |
| Cambridge Scientific Technologies Limited | Wholesale & retail | 2009 |
| Cambridge Technical College - London Ltd | Professional & scientific | 2020 |
| Came Women and Girls Development Organisation | Professional & scientific | 2010 |
| Camedventure Ltd | Information & communication | 2024 |
| Cametan Services Limited | Health & social care | 2023 |
| Campbell Workshop Ltd | Wholesale & retail | 2022 |
| Cams Services Ltd | Health & social care | 2025 |
| Canal Wharf Holdings Ltd | Financial services | 2019 |
| Canal Wharf Properties Limited | Real estate | 2018 |
| Candle Light Childcare Ltd | Education | 2023 |