| Armthorpe Falconry Limited | Doncaster | 2010 |
| Arnavin Farming Ltd | London | 2025 |
| Arnfield FLY Fishery Limited | Manchester | 1993 |
| Arnhall Farms Limited | Angus | 2005 |
| Arnisdale Estate | Kyle | 1987 |
| Arniston Upland Limited | Edinburgh | 2024 |
| Arnold and Sons Landscaping Ltd Ltd | Biddenden | 2026 |
| Arnold Brae Farm Limited | Faversham | 2002 |
| Arnold Farms Limited | Ombersley | 1959 |
| Arnold Lodge Farm Limited | Nottingham | 2012 |
| Arnon Fishing Ltd. | | 2006 |
| Arnot Farms Limited | By Arbroath | 1996 |
| Arnott Knowe Farms Ltd | Larne | 2025 |
| Aroldo Ltd | Lincoln | 2019 |
| Arram Grange Pigs Limited | North Humberside | 1977 |
| Arran Alpacas Limited | Isle Of Arran | 2020 |
| Arran Dennis Ltd | Norwich | 2024 |
| Arran Developments Ltd | Brodick | 2020 |
| Arran Earthworx Ltd | Isle Of Arran | 1987 |
| Arran Energy Ltd. | Isle Of Arran | 2008 |
| Arran Footpaths and Forestry Ltd | Isle Of Arran | 2017 |
| Arran Mushrooms Limited | Isle Of Arran | 2023 |
| Arran Rainforest C.I.C. | Isle Of Arran | 2025 |
| Arran Timber Ltd | Isle Of Arran | 2024 |
| Arras Holdings Limited | York | 2017 |
| Arrest the Pest Ltd | Cheltenham | 2021 |
| Arrijan Farming Ltd | Stonehouse | 2011 |
| Arrivain Fishing Company Limited | North Yorkshire | 1997 |
| Arrol Ltd | Edinburgh | 2026 |
| Arrow Buying and Marketing Company Limited | Leominster | 2003 |
| Arrow Fencing Ltd | Pewsey | 2023 |
| Arrow Fruit Ltd | Shrewsbury | 2025 |
| Arrow Marine Management Limited | Edinburgh | 2018 |
| Arrow Tree Services Ltd | Felixstowe | 2014 |
| Arrowloch Limited | Stirling | 1998 |
| Arsalaan Mahmood Ltd | Cardiff | 2019 |
| ARSUM2 Ltd | London | 2025 |
| Artaine Limited | Matlock | 2007 |
| Artek Design Ltd | Banff | 2025 |
| Artelium Limited | Worthing | 2023 |
| Artemis Academy CIC | Henlow | 2022 |
| Artemis Alpacas Ltd | Liverpool | 2018 |
| Artemis Tree Services Limited | Chesham | 2006 |
| Arthur Edmondson (Farmers) Limited | | 1969 |
| Arthur GEE (Thorney) Limited | Peterborough | 1948 |
| Arthur Marine Ltd | Sittingbourne | 2013 |
| Arthur Markillie Limited | Wisbech | 1958 |
| Arthur Mitchell Limited | Camberley | 1955 |
| Arthur Pooley Limited | Chorley | 1998 |
| Arthur Wright Farms Limited | Cheshire | 1955 |
| Arthurhouse Livestock Ltd | Laurencekirk | 2024 |
| Arthurs Brothers Island-A-Breen Limited | Newtownards | 2018 |
| Arthurs Fabrication Supply Limited | Okehampton | 2007 |
| Arthurs Organics Limited | Grantshouse Duns | 2022 |
| Artifinney Farms Limited | Hillsborough | 2023 |
| Artisan EGG Ltd | Cullompton | 2025 |
| Artisan Leaves Ltd | Abingdon | 2023 |
| Artisan Plants UK Ltd | Llanfairpwllgwyngyll | 2021 |
| Artisandra Limited | Scunthorpe | 2018 |
| Artscape Gardens Limited | Paisley | 2006 |
| Aruba Island Stables Limited | Alfreton | 2020 |
| Arugamama Limited | London | 2025 |
| Arum Estates Limited | Aldermaston | 2010 |
| Arun Meat & Livestock Company Limited | Bognor Regis | 1982 |
| Arun Rural Developments Limited | Arundel | 2007 |
| Arun Tree Company Ltd | Arundel | 2003 |
| Arundel Kerr Produce (East Anglia) Limited | Elsham, Brigg | 2003 |
| Arundel Woodland Products Ltd | Barnham | 2020 |
| Arvakr Fishing Limited | Kirkapol | 2019 |
| Arvikaconsult Ltd | Dornoch | 2011 |
| ARW Equine Services Ltd | Cranbrook | 2023 |
| ARW Marine Ltd | Leven | 2018 |
| Arytir Limited | Porthcawl | 2019 |
| AS & SM Kemp & SON Ltd | Gateshead | 2024 |
| AS Clark Consultants Ltd | Dundee | 2013 |
| AS Contracting Services Ltd | London | 2026 |
| AS Freedom Farm Ltd | Keighley | 2021 |
| AS One Horticulture Ltd | Bristol | 2024 |
| AS Sheep Dipping Ltd | Tewkesbury | 2019 |
| ASA Abiodun Limited | London | 2026 |
| ASA Farming Limited | Burntisland | 2009 |
| Asa's Synergy Services Limited | Forest Row | 2025 |
| Asad Homes & Services Ltd | Stoke-On-Trent | 2026 |
| Asaf Produce Limited | Hoddesdon | 2014 |
| Asak Farm Products Ltd | London | 2022 |
| ASB Livery Limited | Bridgwater | 2012 |
| Asbs Fishing Company Ltd | Fraserburgh | 2020 |
| ASC Marine Ltd | Burra Isle | 2015 |
| Ascendancy Analytics Ltd | Cheshunt | 2025 |
| Ascending Arbs Tree Services Limited | Ingatestone | 2013 |
| Ascent Stud Limited | Eastleigh | 2025 |
| Ascertain (GB) Limited | Driffield | 2005 |
| Asci Limited | London | 2011 |
| Ascot Tree Services Limited | Ascot | 2015 |
| Ascott Farms Limited | Leighton Buzzard | 1973 |
| Asdeal Limited | Milton Keynes | 2019 |
| ASF Consulting Ltd | Crawley | 2017 |
| ASF Contracting Limited | Cirencester | 2025 |
| Asgog Ltd | Oban | 2021 |
| ASH & Roots Ltd | Caernarfon | 2024 |