| Arborfor Limited | Kingsbridge | 1990 |
| Arborforce Group Ltd | Tarporley | 2019 |
| Arborfore Ltd | Downham Market | 2013 |
| Arborglyph Tree Services Ltd | Lincoln | 2020 |
| Arboricare Consultancy Ltd | Wantage | 2022 |
| Arboricare Limited | Somerset | 2006 |
| Arboricultural Association Trading Limited | Stonehouse | 2004 |
| Arboricultural Services Treework Limited | Disley | 2005 |
| Arboricultural Technician Services Limited | Ystradgynlais | 2019 |
| Arboriculture Solutions Ltd | Crewe | 2024 |
| Arborinati Limited | Bathford | 2021 |
| Arboris Holdings Limited | London | 2026 |
| Arboris International Limited | London | 2026 |
| Arborist Training & Consultancy Ltd | Crawley | 2023 |
| Arborista Limited | Morden | 2020 |
| Arborista+ Ltd | Morden | 2025 |
| Arborists N E Ltd | Chester Le Street | 2024 |
| Arborite Tree Services Limited | Newbury | 2008 |
| Arborium Europe Limited | Dulverton | 2011 |
| Arborium North America Limited | Dulverton | 2008 |
| Arborjack Limited | Basildon | 2021 |
| Arborlec Services Limited | Midhurst | 2017 |
| Arborlife Tree Services Ltd | Bookham | 2019 |
| Arbormark Ltd | Birmingham | 2012 |
| Arbormasters Ltd | Ashbourne | 2002 |
| Arborscape Environmental Services Ltd | Workington | 2024 |
| Arborsolve Limited | Norfolk | 2002 |
| Arbortas Ltd | Dartford | 2020 |
| Arbortec NW Ltd | Bolton | 2022 |
| Arbortec Tree Surgery Limited | Manchester | 2013 |
| Arbortech Limited | Godalming | 2012 |
| Arbortech Tree Specialists Limited | North Yorkshire | 2003 |
| Arborteering Ltd | Isle Of Skye | 2006 |
| Arborum Limited | Swansea | 2008 |
| Arborvitae Tree Care Ltd | Poole | 2008 |
| Arborwood Tree Care Limited | Llantwit Major | 2014 |
| Arborworks Ltd | Leatherhead | 2025 |
| Arborzen Ltd | Bridgend | 2024 |
| Arbour Farming Limited | Nantwich | 2017 |
| Arbour Farms Limited | Newport | 2010 |
| Arbour Growers Limited | Gwent | 1997 |
| Arbour House Farm Medical and Agricultural Ltd | Durham | 2021 |
| Arbovia Contracting Ltd | Lymm | 2025 |
| Arbscape Tree Consultancy Ltd | Daventry | 2022 |
| Arbscape Tree Surgeons Ltd | Daventry | 2022 |
| Arbserv Limited | Shrewsbury | 2011 |
| Arbsystem Ltd | Farnham | 2017 |
| Arbtech Consulting Limited | Manchester | 2006 |
| Arbtech Tree Services Ltd | Rhoose | 2012 |
| Arbteck Limited | Wrexham | 2020 |
| Arbuckle Poultry Limited | Dundee | 2014 |
| Arbuckle Soft Fruit Limited | Dundee | 2001 |
| Arbuk Limited | Oxford | 2015 |
| Arbwise Limited | Romsey | 2015 |
| ARC Agronomic Sciences Ltd | Woodbridge | 2024 |
| ARC Exotics Ltd | Milton Keynes | 2019 |
| ARC Farming Ltd | Leominster | 2015 |
| ARC Fishings Limited | St. Andrews | 2018 |
| ARC Infinity UK Limited | Chatham | 2025 |
| ARC Tree Services Limited | Dundee | 2024 |
| ARC Tree Surgery Limited | Stowmarket | 2009 |
| ARC Woodlands Limited | Pembrokeshire | 2007 |
| Arcadia Trading Europe Limited | Grimsby | 2002 |
| Arcadian Marine Ltd | Arbroath | 2018 |
| Arcadian Prospect Ltd | Halland | 2017 |
| Arcane Crab Limited | Newry | 2022 |
| Arcedia Holdings Limited | Mevagissey | 2001 |
| Arcf Test Company Limited | Preston | 2021 |
| Archaean Ltd | Bury St. Edmunds | 2023 |
| Archdale Land Services Limited | Hayle | 2006 |
| Archer Farming Company | Marbury | 2016 |
| Archer Farms (Anglesey) Limited | Llanerchymedd | 1972 |
| Archer-Donaldson Limited | Loughborough | 2025 |
| Archerfield Estates Ltd | Kelso | 1987 |
| Archers @ Red Bank Farm Limited | Lancaster | 2017 |
| ARCHERS25 Ltd | Tredegar | 2023 |
| Archersway Game & Gundogs Ltd | Alton | 2014 |
| Arches Hall Stud Limited | London | 2024 |
| Archewell Stables Ltd | Cookstown | 2021 |
| Archifarmlab Limited | Ely | 2014 |
| Architectural Engineering & Manufacturing Design Company Limited | Ballyclare | 1984 |
| Architectural Plants 2020 Limited | Pulborough | 2020 |
| Architectural Plants Limited | Reigate | 1990 |
| Archtomtom Ltd | London | 2023 |
| Archville Limited | Newry | 1989 |
| Archwill Bloodstock Limited | Edinburgh | 2020 |
| Arcoppe Limited | Cardiff | 2023 |
| Arcswood C.I.C. | Pembroke | 2011 |
| Arctantar Ltd | London | 2022 |
| Arctic Gold Limited | Derby | 2010 |
| Arcus Ventures Ltd | Surtees Business Park | 2013 |
| ARD - Dorragh Cattle Breeders Ltd. | Coleraine | 1988 |
| ARD Pest Control Ltd | Monmouth | 2009 |
| Ardardan Estate Ltd. | Dumbarton | 2006 |
| Ardbhan Genetics Ltd | Isle Of North Uist | 2025 |
| Arden Country Services Ltd | Henley-In-Arden | 2021 |
| Arden Farms Limited | Market Rasen | 1988 |
| Arden Farms Owmby Ltd | Market Rasen | 1947 |
| Arden Farriers Limited | Warwick | 2026 |
| Arden Fields Equestrian Limited | Solihull | 2004 |