| Buggy PIT Stop Ltd | Other services | 2013 |
| Build I.T. Consulting Ltd | Information & communication | 2005 |
| Buildex Ltd | Construction | 2013 |
| Building Construction and Innovation Ltd | Construction | 2019 |
| Building Services and Support Limited | Construction | 2015 |
| Builds R US Limited | Construction | 2021 |
| Buildsimple Cloud Solutions Ltd | Information & communication | 2017 |
| Buildtrade Ltd | Construction | 2021 |
| Buldrive Ltd | Transport & logistics | 2014 |
| Bullet Tooth Ltd | Arts & recreation | 2025 |
| Bumblebee&Co Limited | Hospitality | 2023 |
| Buoyant Civil Engineering Ltd | Professional & scientific | 2025 |
| Burdusel Ltd | Transport & logistics | 2017 |
| Burgrill Limited | Hospitality | 2019 |
| Burlington Accountancy Services Limited | Professional & scientific | 2010 |
| Busheller Bars Limited | Hospitality | 2024 |
| Business Knowledge Consulting Limited | Information & communication | 2025 |
| Business Lawyers Limited | Professional & scientific | 2003 |
| Business Loan 4 U Limited | Other services | 2025 |
| Business Propeller Limited | Professional & scientific | 2023 |
| Butler & Hidri Holdings Limited | Households | 2025 |
| Butler Chicks Properties Ltd | Real estate | 2021 |
| Butterfly Advisory Limited | Information & communication | 2012 |
| Button Nation Limited | Construction | 2010 |
| Buy and Rent for Good Limited | Real estate | 2026 |
| Buy Britain Limited | Professional & scientific | 2022 |
| Buytoletworld Limited | Real estate | 2015 |
| Byron Building & Roofing Limited | Construction | 2013 |
| Byron Lodge (West Melton) Limited | Health & social care | 2014 |
| Byron Scaffolding Ltd | Administrative & support | 2011 |
| Byron Way Management Limited | Real estate | 1999 |
| Bytebloom Limited | Information & communication | 2019 |
| Bytebridge Technology Limited | Wholesale & retail | 2023 |
| BZ Construction Ltd | Construction | 2015 |
| C H Carpentry & Joinery Limited | Construction | 2010 |
| C K Medical Limited | Health & social care | 2025 |
| C Mcgarvey Developments Limited | Real estate | 2025 |
| C Turner Photo Limited | Professional & scientific | 2014 |
| C&G Capital Ltd | Financial services | 2023 |
| C-Mobile Limited | Hospitality | 2024 |
| C. Mehta & Co Limited | Wholesale & retail | 1999 |
| C2 Furniture Contracts Limited | Wholesale & retail | 2002 |
| Caas Associates UK Limited | Information & communication | 2021 |
| Cadeau Ltd | Information & communication | 2014 |
| Cafe Alizey Limited | Hospitality | 2018 |
| Cafe Paradiso Deli Limited | Manufacturing | 2006 |
| Caffeina Limited | Hospitality | 2013 |
| Caines Chemical Engineering Limited | Professional & scientific | 1997 |
| Cajc Limited | Financial services | 2025 |
| Cake Box Finchley Limited | Wholesale & retail | 2017 |
| Cakebox Edgware Limited | Manufacturing | 2021 |
| Calibre Productions Limited | Administrative & support | 1999 |
| Calico RE Ltd | Professional & scientific | 2020 |
| Callachand Garages Limited | Wholesale & retail | 2005 |
| Calum Currie Studios Limited | Information & communication | 2023 |
| CAM & Co Accountancy Ltd | Professional & scientific | 2009 |
| Camas Developments Limited | Construction | 2007 |
| Camb Co. NO. 2 Ltd | Administrative & support | 2010 |
| Camden B&B Limited | Administrative & support | 2014 |
| Cameo IP Limited | Professional & scientific | 2026 |
| Camerich UK Limited | Wholesale & retail | 1998 |
| Camroc Developments Ltd | Construction | 2026 |
| Camusterrach Limited | Extraterritorial | 2022 |
| Candida Limited | Real estate | 2003 |
| Candy Store Express Limited | Wholesale & retail | 2005 |
| Cannon Barn Montessori School Ltd | Education | 2014 |
| Canons Park Assets Limited | Real estate | 2019 |
| Canvs Ltd | Professional & scientific | 2020 |
| Capital Business Coaching Ltd | Professional & scientific | 2017 |
| Capital Commodity Consultants Limited | Wholesale & retail | 2012 |
| Capital Essence Ltd | Professional & scientific | 2016 |
| Capital Events Entertainment Ltd | Professional & scientific | 2010 |
| Capital Investment and Finance Ltd | Real estate | 2001 |
| Capital Investment Floor Ltd | Financial services | 2026 |
| Capital Roofing & Guttering Limited | Professional & scientific | 2001 |
| Capital Search Limited | Administrative & support | 2007 |
| Cappard Estates (CW) Limited | Construction | 2024 |
| Cappard Estates (HD) Limited | Construction | 2023 |
| Cappard Estates (LH) Limited | Construction | 2021 |
| Cappard Estates (TY) Limited | Real estate | 2021 |
| Cappard Estates Limited | Construction | 2014 |
| Cappard Finance Limited | Financial services | 2019 |
| Capri Italia Ltd | Hospitality | 2025 |
| Capricorn HR Consulting Ltd | Administrative & support | 2023 |
| Capricorn Partners Limited | Energy | 2014 |
| Capstone Analytics Limited | Information & communication | 2025 |
| Capstone Communication Services Limited | Professional & scientific | 2002 |
| Capvia Limited | Real estate | 2025 |
| Card Voyage Ltd | Wholesale & retail | 2025 |
| Cardiac Health Ltd | Health & social care | 2014 |
| Cardiothoracic Anaesthesia Partnership Limited | Education | 2022 |
| Care Consort Ltd | Information & communication | 2022 |
| Care Plus London Limited | Health & social care | 2023 |
| CARE4TALENTS Limited | Administrative & support | 2023 |
| Careerwiz Limited | Professional & scientific | 2023 |
| Caregreen Ltd | Professional & scientific | 2001 |
| Carey Services Ltd | Real estate | 2023 |
| Caritas Holdings Limited | Financial services | 2022 |
| Caritas Medical Services Limited | Health & social care | 2017 |
| Carleo Property Holdings Limited | Real estate | 2018 |