| Aegean Trips Ltd | London | 2022 |
| Aegis (UK) Group Ltd | Abingdon | 2012 |
| Aegis 48 Limited | Huddersfield | 2018 |
| Aegis Insurance Consultants Limited | Pembrokeshire | 2001 |
| Aegis Research and Analysis Ltd | London | 2023 |
| Aegis Techmed Ltd | London | 2025 |
| Aegis Training Consultancy Limited | Cardiff | 2016 |
| AEI Electronics Limited | Southampton | 2011 |
| Aejb Trading Ltd | Bournemouth | 2011 |
| AEL Limited | Newton Aycliffe | 1978 |
| AEL Outdoor Solutions Limited | Reading | 2015 |
| AEL Solutions Limited | Reading | 2015 |
| Aeltrix Vesper Ltd | London | 2025 |
| AEM Trustees Limited | Belfast | 2023 |
| Aemg Ltd | Holywood | 2012 |
| Aenclave Ltd | Newcastle Upon Tyne | 2020 |
| Aeneas Iron & Steel Limited | London | 2009 |
| Aeneas Sailing Ltd | London | 2025 |
| Aeolus Landhouse Ltd | London | 2020 |
| Aeomica Ltd | Daresbury | 2009 |
| Aeon UK Limited | Milton Keynes | 2005 |
| Aeonic Radio Limited | London | 1988 |
| Aeonium Limited | Birmingham | 2023 |
| AEP Cleaning Services Limited | Southend-On-Sea | 2019 |
| Aepos UK Ltd | Corby | 2021 |
| AEQ Ltd | London | 2024 |
| Aequalia Limited | Romsey | 2014 |
| Aequilibrium Limited | Hornchurch | 2012 |
| Aequus Belfast Ltd | Newtownards | 2013 |
| AER Management Services Ltd | Manchester | 2014 |
| Aereum Ltd | Newry | 2024 |
| Aergard Ltd | Durham | 2026 |
| Aerial & Satellite Communications Limited | Crosby | 1989 |
| Aerial Access Limited | Carnforth | 2006 |
| Aerial Film and Photo Limited | Marlow | 2024 |
| Aerial Unit Limited | London | 2021 |
| Aerivox Holdings Ltd | Doncaster | 2026 |
| Aern Capital Limited | London | 2022 |
| Aero Gears Limited | Chesterfield | 2012 |
| Aero Medical Ambulance Service Ltd | London | 2016 |
| Aero Sport International Limited | Macclesfield | 2008 |
| Aero Team Model Distribution Ltd. | Dorchester | 2014 |
| Aerobics Limited | | 1992 |
| Aeroblu Ltd | London | 2025 |
| Aeroblue Limited | Glasgow | 1998 |
| Aerodex Floyd Limited | | 1987 |
| Aerogen Limited | Alton | 2011 |
| Aerogenesis UK Limited | London | 2011 |
| Aeroglow Limited | High Wycombe | 2014 |
| Aeroknow Limited | Letchworth | 2026 |
| Aerolume Ltd | London | 2025 |
| Aeromark Environmental Technologies Ltd | Bedford | 2013 |
| Aeromorphia Ltd | Dover | 2022 |
| Aeronautica at Southampton Ltd | Romsey | 2009 |
| Aeronavia Limited | Newcastle Upon Tyne | 1986 |
| Aeropets UK Limited | Sunbury-On-Thames | 2010 |
| Aeroplane Creative Ltd | Manchester | 2015 |
| Aeropt Ltd | London | 2025 |
| Aerospace & Industrial Controls Limited | Poole | 2016 |
| Aerospace Aluminum Co., Ltd | Beckenham | 2013 |
| Aerospace Electronics Ltd. | London | 2004 |
| Aerospace Gears Limited | Chesterfield | 2012 |
| Aerospace Surface Treatments Ltd. | Stansted | 1996 |
| Aerospy Ltd | King'S Lynn | 2025 |
| Aerostar Technologies Limited | York | 2025 |
| Aerostocks Limited | Rayleigh | 2016 |
| Aerotech Inspection & NDT Limited | London | 2004 |
| Aerotech Management Ltd | St. Neots | 2024 |
| Aerovue Limited | Inverurie | 2014 |
| Aertrola Limited | Walsall | 2020 |
| Aerweitasi (Finland) Group Chemical Industry Ltd | Beckenham | 2025 |
| AES Commercial Properties Limited | Hampshire | 1998 |
| AES Hampshire Ltd | Portsmouth | 2024 |
| AES Renewables Ltd | Forres | 2025 |
| AES Security Limited | London | 1998 |
| AES Transport Limited | London | 2025 |
| Aesculap Academia Co. Ltd. | Chapeltown, Sheffield | 1996 |
| Aesir Consultancy Group Ltd | Catterick Garrison | 2022 |
| Aesir Technologies UK Limited | Milton Keynes | 2021 |
| Aesrex Ltd | Kington | 2026 |
| Aesrhea Laboratories Limited | Cardiff | 2018 |
| Aesthemed Ltd. | London | 2008 |
| Aesthetex Supplies Limited | Lichfield | 2022 |
| Aesthetic Arch FM Ltd | Sheffield | 2025 |
| Aesthetic Cart Ltd | Essex | 2024 |
| Aesthetic Clinic Ealing Limited | London | 2019 |
| Aesthetic Integration Research Limited | London | 2014 |
| Aesthetic Meducation Limited | Spennymoor | 2023 |
| Aesthetic Purposes Only Ltd | Bristol | 2025 |
| Aesthetic Sweetheart Ltd | Shefford | 2024 |
| Aesthetic Widgets Ltd | London | 2023 |
| Aesthetics Adept Limited | London | 2022 |
| Aesthetics Collective Limited | Ipswich | 2020 |
| Aesthetics Refined Limited | Slough | 2017 |
| Aether Collective Limited | London | 2017 |
| Aether Summit Global Investments Ltd | Manchester | 2025 |
| Aetherrise Ltd | London | 2025 |
| Aethos Limited | Barnet. | 2016 |
| Aetn Creations Ltd | Alva | 2024 |
| Aetp Trustee Company Limited | Omagh | 2018 |