| J.W.Burgess & Sons Limited | Cambridge | 1954 |
| J.W.Cousins & Sons(Farmers)Limited | Brigg | 1965 |
| J.W.E.Banks,Limited | Peterborough | 1951 |
| J.W.Finding(Farms)Limited | Southampton | 1963 |
| J.W.Franklin Limited | Hitchin | 1964 |
| J.W.J. Tideswell Limited | Stoke-On-Trent | 2014 |
| J.W.Kirkham & Sons | Lytham St. Annes | 1961 |
| J.W.Padfield Limited | Royston | 1957 |
| J.W.R.Beckitt(Hill Farm,Egmanton)Limited | Newark | 1964 |
| J.W.Spencer Farms Limited | Thetford | 1966 |
| J.W.Thomas & Sons(Farms)Limited | Brackley | 1961 |
| J.W.Thompson(Whitefield)Limited | Morpeth | 1959 |
| J.Ward & Son(Farms) | Leiston | 1949 |
| J1D Ltd | Tunbridge Wells | 2025 |
| JA & WA Proctor Limited | Driffield | 2002 |
| JA Birkbeck Limited | Thirsk | 2024 |
| JA Farming Ltd | Ipswich | 2024 |
| JA Hopkinson & SON Ltd | Chesterfield | 2022 |
| JA Renewable & Plumbing Solutions Ltd | Shrewsbury | 2023 |
| JA Wood Limited | Hereford | 2026 |
| Jacamar Fishing Ltd | | 2008 |
| Jacinta Limited | Ferriby Road Hessle | 1987 |
| Jack AG Services Limited | Stoke-On-Trent | 2015 |
| Jack and EVE Fishing Limited | Plymouth | 2026 |
| Jack Baker Limited | Fordingbridge | 1948 |
| Jack Barnes (Farming) Limited | Clitheroe | 1973 |
| Jack Bradford Hire Ltd | Brigg | 2022 |
| Jack Buck (Farms) Limited | Spalding | 2010 |
| Jack Buck (Holdings) Limited | Spalding | 1959 |
| Jack Cotterill Tree Services Limited | Droitwich | 2014 |
| Jack Davies Contracting Limited | Port Talbot | 2025 |
| Jack Edwards Farms Limited | Barnet | 2002 |
| Jack Fisheries Ltd | Elgin | 2015 |
| Jack Foster Ltd | Skipton | 2024 |
| Jack Goddard Farrier Services Ltd | Reading | 2019 |
| Jack Godden Agri Ltd | Folkestone | 2023 |
| Jack Harvey Ltd | Loughborough | 2025 |
| Jack Jones Racing Ltd | Newmarket | 2022 |
| Jack Leason Ltd | Burton-On-Trent | 2015 |
| Jack Merricks Farms (RYE) Limited | Winchelsea | 1960 |
| Jack Nicoll Farms Limited | | 1975 |
| Jack Pine Trees Ltd | Bristol | 2010 |
| Jack Pinkney Livery Ltd | Newbury | 2022 |
| Jack RB Ltd | Shipston-On-Stour | 2016 |
| Jack Robinson (Trawlers) Limited | London | 1946 |
| Jack Russell Terrier Rescue UK CIC | Rochford | 2017 |
| Jack Sleigh & Sons Limited | Aberdeen | 1977 |
| Jack's Patch Limited | Upminster | 2020 |
| Jackal Enterprises Limited | Benfleet | 1980 |
| Jackamax Limited | Plymouth | 2012 |
| Jackie Johnston Limited | Melrose | 2013 |
| Jackmans Down Limited | Okehampton | 2026 |
| Jacks Farm Services Limited | Taunton | 2011 |
| Jackson Agri Engineering Ltd | Oswestry | 2012 |
| Jackson Marine Services Limited | Argyll | 2026 |
| Jackson Poultry Ltd | Antrim | 2013 |
| Jackson Pumping Ltd | Dinton | 2016 |
| Jackson's Farm Limited | Church Accrington | 2002 |
| Jackson's Nurseries (U.K.) Ltd. | Stoke-On-Trent | 1991 |
| Jackson-Kelly Ltd | Liverpool | 2024 |
| Jacksons Farm and Forest Ltd | Nottingham | 2014 |
| Jacksons Wold Eggs Limited | Malton | 2024 |
| Jacktar Graeme Ltd. | Fraserburgh | 2003 |
| Jackton Estates Limited | Glasgow | 2012 |
| Jacob Agri Ltd | Swansea | 2024 |
| Jacob Lewis Trees Limited | Swansea | 2015 |
| Jacob's Flock Ltd. | Sandy | 2013 |
| Jacob's Ladder Farms Limited | East Grinstead | 2014 |
| Jacobs Ridge Sanctuary Ltd | London | 2024 |
| Jade (Eco) Ltd | Derby | 2026 |
| Jade Ellery Dressage Ltd | Chipping Norton | 2021 |
| Jade Green International Trading Co., Ltd. | Beckenham | 2021 |
| Jadeleigh Electrical Ltd. | Fraserburgh | 2003 |
| JAE Whittingham Ltd | Shrewsbury | 2022 |
| JAF Farming Limited | North Yorkshire | 1998 |
| JAF Products (UK) Limited | Cardiff | 2009 |
| JAG Sport Horses Ltd | Cardiff | 2021 |
| JAH Stump Grinding Ltd | Baildon | 2025 |
| Jahero Limited | Rutland | 2025 |
| Jake Bingham Farriery Limited | Hertford | 2026 |
| Jake COX Limited | Stanstead Abbotts | 2014 |
| Jake Elliott Equestrian Limited | Retford | 2014 |
| Jake Eville Tree Care Ltd | Dronfield | 2025 |
| Jake Wain Contracting Limited | Carmarthen | 2024 |
| Jake's Adventures Petcare Ltd | Doncaster | 2019 |
| Jako's Group Limited | Ipswich | 2017 |
| Jalapeno Ventures Ltd | Lincoln | 2018 |
| Jalex Farms Limited | Antrim | 2017 |
| Jalex Livestock Ltd | Antrim | 2026 |
| Jalhar Beagles Limited | Stoke-On-Trent | 2020 |
| Jalna Marine Services Limited | Middlesbrough | 2009 |
| Jalving Potatoes UK Ltd | Telford | 2006 |
| JAM Lass Racing Limited | York | 2022 |
| Jamaldini Limited | Leicester | 2025 |
| Jamar Fishing Ltd. | Fraserburgh | 2006 |
| James & Charnley Farm Ltd | Clynderwen | 2023 |
| James a Watson Ltd | Ochiltree | 2012 |
| James a. Gibson & Co. (Cowgrove) Limited | Galston | 1957 |
| James Adams Eventing Limited | Stockton On Tees | 2018 |
| James Allison Farming Limited | Middleton Tyas | 2023 |