| Avenue Cleaning (Norwich) Ltd | Administrative & support | 2025 |
| Avenue East Rentals Ltd | Real estate | 2023 |
| Avenue Road Wymondham (Management) Limited | Households | 2003 |
| Aver P Limited | Wholesale & retail | 2025 |
| Averel Limited | Professional & scientific | 2013 |
| Avery Building & Construction Ltd | Construction | 2015 |
| Avery Inspection Services Limited | Mining & quarrying | 2002 |
| Avgmedical Ltd | Health & social care | 2025 |
| AVH Plumbing and Heating Midlands Ltd | Construction | 2021 |
| AVHOLDINGS37 Ltd | Hospitality | 2019 |
| Aviait Services Limited | Professional & scientific | 2006 |
| Avian Dance School Ltd | Arts & recreation | 2019 |
| Aviatek Dynamics Ltd | Transport & logistics | 2022 |
| Aviation and Marine Engineering Limited | Manufacturing | 1982 |
| Aviation Consult Limited | Professional & scientific | 2018 |
| Avie Networks Limited | Information & communication | 2002 |
| Aviorace UK Limited | Wholesale & retail | 2025 |
| Aviv Ideation and Consulting UK Limited | Professional & scientific | 2023 |
| Aviva Central Services UK Limited | Other services | 1996 |
| Aviva Credit Services UK Limited | Financial services | 1922 |
| Aviva UK Digital Limited | Financial services | 2015 |
| AVL Coatings Ltd | Construction | 2025 |
| AVMECH2 Ltd | Manufacturing | 2024 |
| Avocet Environmental Services Limited | Construction | 2023 |
| Avocet Farming Ltd | Agriculture & fishing | 2020 |
| Avoncliff Software Limited | Information & communication | 2010 |
| Avonmouth Data Centre Limited | Information & communication | 2026 |
| Avsp Ltd | Information & communication | 2012 |
| AW Developments Anglia Limited | Construction | 2022 |
| Awae Consulting Limited | Professional & scientific | 2026 |
| Awais Go Ltd | Transport & logistics | 2026 |
| Awake Workshops CIC | Arts & recreation | 2023 |
| Awesome Construction Ltd | Construction | 2013 |
| AWN Developments Ltd | Financial services | 2020 |
| AWS Oven Cleaning Limited | Administrative & support | 2023 |
| Axact 247 Limited | Construction | 2020 |
| AXE Link Limited | Transport & logistics | 2019 |
| Axiom Surveying Limited | Professional & scientific | 2026 |
| Axis Paving Ltd | Administrative & support | 2026 |
| Axium Partners Limited | Professional & scientific | 2025 |
| AXL Freight Ltd | Transport & logistics | 2021 |
| AXT3N Offshore Ltd | Mining & quarrying | 2025 |
| AXT3N Property Ltd | Real estate | 2023 |
| AYA Hockey Limited | Wholesale & retail | 2019 |
| AYA Yousif Limited | Health & social care | 2023 |
| Ayaa Botanicals Ltd | Wholesale & retail | 2024 |
| AYB Projects Ltd | Real estate | 2021 |
| Ayers Plumbing and Heating Ltd | Construction | 2025 |
| Aylaa Exclusive Limited | Professional & scientific | 2015 |
| Aylaabigail Limited | Health & social care | 2021 |
| Aylmerton Field Study Centre Ltd | Arts & recreation | 2018 |
| Aylmerton Outdoor Education Centre Ltd | Arts & recreation | 2018 |
| Aylsham Analytics Limited | Information & communication | 2021 |
| Aylsham Autos Limited | Wholesale & retail | 2023 |
| Aylsham Capital Ltd | Real estate | 2020 |
| Aylsham Carpets and Flooring Limited | Wholesale & retail | 2023 |
| Aylsham Cluster Trust | Education | 2011 |
| Aylsham Community Church | Other services | 2004 |
| Aylsham Community Partnership | Arts & recreation | 2006 |
| Aylsham Community Sports Limited | Arts & recreation | 2014 |
| Aylsham Developments & Construction Ltd | Construction | 2025 |
| Aylsham Dog Walking Limited | Other services | 2023 |
| Aylsham DRY Cleaning Services Limited | Other services | 2009 |
| Aylsham Football Club Limited | Arts & recreation | 2013 |
| Aylsham Garden Centre Limited | Agriculture & fishing | 2020 |
| Aylsham Mill Management Company Limited | Households | 2016 |
| Aylsham MOT Centre Ltd | Extraterritorial | 2024 |
| Aylsham Plant Hire Holdings Limited | Administrative & support | 2019 |
| Aylsham Plant Hire Limited | Administrative & support | 1973 |
| Aylsham Roofing Ltd | Construction | 2024 |
| Aylsham Roofing Services Ltd. | Construction | 2018 |
| Aylsham Slurry Services Ltd. | Water & waste | 1998 |
| Aymerhan Ltd | Hospitality | 2025 |
| Ayodapo Limited | Wholesale & retail | 2024 |
| AYS Food Ltd | Hospitality | 2018 |
| AZ Motors Norwich Ltd | Wholesale & retail | 2025 |
| AZ Properties Norwich Ltd | Real estate | 2025 |
| Azaiba Consult Ltd. | Professional & scientific | 2022 |
| Azaoat Taxi Transit Ltd | Transport & logistics | 2026 |
| Azem Ltd | Wholesale & retail | 2024 |
| AZI Property Management Ltd | Real estate | 2026 |
| AZL Solutions Limited | Information & communication | 2019 |
| Azone Ltd | Wholesale & retail | 2019 |
| Azoth Group Ltd | Financial services | 2024 |
| Azoth Investments Ltd | Financial services | 2022 |
| Azoth Solutions Ltd | Professional & scientific | 2016 |
| Azur Events Limited | Hospitality | 2011 |
| Azure Outdoor Living Limited | Construction | 2020 |
| Azured (UK) Ltd | Information & communication | 2019 |
| AZY Taxis Ltd | Transport & logistics | 2025 |
| Azzon Properties Ltd | Real estate | 2019 |
| B & C Estates Limited | Real estate | 2020 |
| B & D Developers Ltd | Construction | 2015 |
| B & D Property Rental Limited | Real estate | 2018 |
| B & F GAS Services (Anglia) Limited | Administrative & support | 2005 |
| B & H Windows & Conservatories Ltd | Construction | 2014 |
| B & P Installations Ltd | Construction | 2012 |
| B & S Imports and Exports Ltd | Wholesale & retail | 2018 |
| B a Wheels Limited | Wholesale & retail | 2012 |
| B Beales Developers Holdings Ltd | Financial services | 2026 |