| Fionabooyceramics Ltd | St. Albans | 2005 |
| Fionnlocha Wild Nature Sanctuary Ltd | Lewes | 2025 |
| Fionntan Lawlor Golf Limited | Tandragee | 2025 |
| Fiorentini Arts School Limited | Swindon | 2008 |
| Fiorentini Foundation | London | 2010 |
| Fiori Musicali Limited | Daventry | 1991 |
| FIQ Ltd | Preston | 2024 |
| FIR Tree Farm Equestrian Centre Limited | Berwick Upon Tweed | 2012 |
| FIR Tree Theatre C.I.C. | Oxford | 2024 |
| Firas & Hadi Coaching Ltd | Enfield | 2026 |
| Firat Archaeological Services Ltd. | Helensburgh | 2008 |
| Firbank Kempster Integrated Communications Partnership Limited | 56 Dingwall Road | 1984 |
| Fircroft Wildlife Ltd | Carlisle | 2025 |
| Fire & Flight Ltd | St. Neots | 2019 |
| Fire and Dust Ltd | Totnes | 2011 |
| Fire and Flux Ceramics Limited | Norwich | 2016 |
| Fire at the Disco Ltd | Sheffield | 2021 |
| Fire Blood and Steel Ltd | Tadcaster | 2023 |
| Fire by the River Ltd | Manchester | 2011 |
| Fire Design Paris Limited | Bristol | 2002 |
| Fire Fitness Falkirk Ltd | Falkirk | 2023 |
| Fire Global Media Productions Limited | Chatham | 2010 |
| Fire in the Mountain Festival Limited | Aberystwyth | 2012 |
| Fire in the Mountain Production Ltd | London | 2019 |
| Fire Installation Services Limited | Sheffield | 1994 |
| Fire Instenk Ltd | London | 2025 |
| Fire IT UP Limited | Wigan | 2004 |
| Fire Light Design & Project Management Ltd | Bedford | 2008 |
| Fire Monkey Fireworks Limited | Dudley | 2023 |
| Fire Monkey Pyro Ltd | Dudley | 2025 |
| Fire Prizes Ltd | London | 2020 |
| Fire Promotion Music Production Ltd | London | 2019 |
| Fire Ride Ltd | Leicester | 2023 |
| Fire Station Creative Limited | Dunfermline | 2013 |
| Fire Station Creative Trading Limited | Dunfermline | 2014 |
| Fireball Beach Volleyball Ltd | Barnstaple | 2021 |
| Fireball Leisure Limited | Bolton | 2011 |
| Fireball North Devon Volleyball Club Ltd | Braunton | 2024 |
| Fireball Sessions Ltd | London | 2020 |
| Firebird & Bluebird Firework Displays & Entertainments (UK) Limited | Aldershot | 1997 |
| Firebird Firewalks Limited | Walsall | 2025 |
| Firebird Theatre | Bristol | 2006 |
| Firebrand Artisans Limited | Shaftesbury | 2013 |
| Firebrand Theatre Company Limited | London | 2011 |
| Firebreather Ltd | Bedworth | 2013 |
| Firecracker Creative Limited | Ipswich | 2012 |
| Firecrow Ltd | Wellingborough | 2024 |
| Fired 4 U Limited | Clitheroe | 2011 |
| Fired Art Limited | Ryde | 2022 |
| Fired on Friday Famous by Monday Ltd | Warrington | 2026 |
| Fired UP Fitness Limited | Bicester | 2025 |
| Fired UP Theatre Company Limited | Walsall | 2006 |
| Firedup Pottery Ltd | Gateshead | 2025 |
| Firefest Ltd | Stockport | 2023 |
| Firefight ABC Ltd | Leeds | 2024 |
| Firefight Nxtgen CIC | Fleet | 2025 |
| Firefight Productions Ltd | Coatbridge | 2026 |
| Firefighter Heritage Centre Limited | Swanley | 2015 |
| Firefighters 66 Ltd | Newport | 2023 |
| Firefite Boxcross Ltd | Norwich | 2023 |
| Firefithq Ltd | Carluke | 2025 |
| Fireflow Entertainment Ltd | Norwich | 2021 |
| Fireflow Ltd | Wisbech | 2012 |
| Fireflow Studios Ltd | Wimborne | 2026 |
| Firefly Arts Limited | Livingston | 1990 |
| Firefly Cage Limited | Abingdon | 2006 |
| Firefly Gymnastics Academy Limited | Cardiff | 2025 |
| Firefly Jars Entertainment UK Limited | Bromsgrove | 2024 |
| Fireflylive Ltd | Dorking | 2018 |
| Firefoot International Limited | Shipley | 2015 |
| Firehand Limited | Watford | 2015 |
| Firehills Designs Limited | Wadhurst | 2025 |
| Firehorse Entertainment Ltd | Sunderland | 2026 |
| Firelights Corp Ltd | Wolverhampton | 2023 |
| Fireman's Farm Limited | Swanley | 2014 |
| Fireparty Ltd | Brighton | 2008 |
| Firepit Art Gallery & Studios CIC | London | 2024 |
| Firepony Limited | London | 2012 |
| Fireproof Talent Ltd | London | 2011 |
| Fireraisers Theatre Company | Brighton | 1998 |
| Fireside Historical Events Ltd | Redhill | 2023 |
| Firewalker (UK) Ltd | Birmingham | 2005 |
| Firewater U.K. Ltd | Glasgow | 2023 |
| Firework Crazy Limited | Dunmow | 2003 |
| Firework Store Limited | Thatcham | 2000 |
| Fireworks Clay Studios | Cardiff | 2004 |
| Fireworks Media Ltd | Kington | 2025 |
| Fireworks Solutions Limited | Dorset | 2007 |
| Firle Bonfire Society Limited | Polegate | 1997 |
| Firle Limited | Firle | 2010 |
| Firle Place Preservation Trust Limited | Lewes | 1982 |
| Firm Balls Limited | Hailsham | 2011 |
| Firma Sports Agency Limited | Wirral | 2015 |
| Firmament Ltd | Bromsgrove | 2007 |
| Firmament Movie Ltd | Upminster | 2024 |
| Firmset Limited | Devon | 1982 |
| Firoka (Beadlow Manor) Limited | | 2001 |
| Firoka (Oxford Cinema) Limited | | 2003 |
| Firoka (Oxford United Stadium) Limited | London | 1999 |
| Firomy Limited | Oxford | 2018 |