| Festival in a Box Limited | Chippenham | 2011 |
| Festival of Wildlife Ltd | Alresford | 2012 |
| Festival Staff Ltd | Chesterfield | 2022 |
| Festivall Staff Ltd | Chesterfield | 2021 |
| Festivapp Limited | Chesterfield | 2023 |
| Festive Footprints Limited | Pagham | 2000 |
| Festivve Limited | London | 2020 |
| Festo Chemical Ltd | Stafford, | 2012 |
| Fetcher and Gatherer Ltd | London | 2025 |
| Fevore Investments Limited | Bletchley | 2016 |
| Fewco Sports Ltd | Cobham | 2015 |
| Fewsters (Plant Services) Limited | Newcastle | 1964 |
| Fewston Limited | Leeds | 2019 |
| FEY (UK) Limited | Poole | 2001 |
| Feydar Ltd | London | 2024 |
| FEZ Mangal Limited | Ilford | 2013 |
| FEZ Trading Ltd | Manchester | 2011 |
| FF Poplar Trustee Limited | London | 2020 |
| FF Retail (Telford) Ltd | Shrewsbury | 2015 |
| FF Worldwide Ltd | London | 2016 |
| FFA Engineering Limited | Penrith | 2023 |
| FFA Holdings Ltd | Glasgow | 2021 |
| FFC Holdings Limited | Droitwich Spa | 2016 |
| FFE DEV1 Ltd | Bridlington | 2025 |
| FFE LH1 Ltd | Bridlington | 2025 |
| Ffenestri Cymru Windows Ltd | Bangor | 1997 |
| FFL Properties Limited | Doncaster | 2024 |
| Fflat Four Restoration Limited | Wrexham | 2023 |
| Ffora UK Ltd | Cardiff | 2020 |
| Fforest Green Limited | Cowbridge | 2011 |
| FFP Technology Ltd | Leigh-On-Sea | 2023 |
| Ffridd Elin Residents Management Company Ltd | Barmouth | 2024 |
| FFT Company Secretarial Limited | Manchester | 2006 |
| FFY Trafford Ltd | Rochdale | 2025 |
| FG Adamson and SON Limited | Ripon | 2023 |
| FG Aila Limited | Bromley | 2022 |
| FG Education Services Ltd | Bristol | 2020 |
| FG Furniture Group Ltd | London | 2015 |
| FG Management Limited | London | 2014 |
| FG MED Limited | Kilmarnock | 2012 |
| FG Wilson (Engineering) Limited | Peterborough | 1989 |
| FG Yachting Ltd | London | 2025 |
| Fgas Holdings Limited | Wotton-Under-Edge | 2013 |
| FGC Investments Limited | London | 2016 |
| FGS Rentals Limited | Aylesford | 1990 |
| FGT Commercial Limited | Attleborough | 2013 |
| FGT Corporate Ltd | Rossendale | 2024 |
| FGT Domestic Limited | Attleborough | 2013 |
| FGT Systems Limited | Attleborough | 2013 |
| FH & a Invest Ltd | London | 2018 |
| FH Consulting Limited | Isleworth | 2015 |
| FH Trading Holding Limited | London | 2023 |
| FH Trading Investment Limited | London | 2023 |
| Fheo Limited | Thatcham | 2019 |
| FHH Developments Limited | Sheffield | 2015 |
| FHL Care Limited | Harold Wood | 2017 |
| FHL Namesaver Limited | London | 2021 |
| FI Knowledge MAP Limited | Truro | 2002 |
| FI2Q UK Limited | London | 2013 |
| Fiabi Care Limited | Bedford | 2014 |
| Fiac UK Limited | Manchester | 1990 |
| Fiacom International Trading Co., Ltd | Beckenham | 2017 |
| Fiamma Sales Ltd | Northampton | 2012 |
| Fibatube Limited | Leeds | 1968 |
| Fiber Invest Limited | London | 2011 |
| Fiber Packaging Co., Ltd | Cambridge | 2018 |
| Fiber Technologies Ltd | Crowthorne | 2019 |
| Fiber Telecom Ltd | London | 2010 |
| Fibergo Telecom Co., Ltd | Kenilworth | 2017 |
| Fiberlink Group Ltd. | London | 2019 |
| Fiberpay Limited | London | 2025 |
| Fibertek U.K. Limited | Bury | 1997 |
| Fibonacci Guitars Ltd | London | 2015 |
| Fibox (UK) Limited | Stockton-On-Tees | 1996 |
| Fibre Infrastructure Installation Services Ltd | Telford | 2019 |
| Fibre Optics Centre Limited | Tunbridge Wells | 1997 |
| Fibre Superiore Limited | Halifax | 2004 |
| Fibrefine Textiles (Huddersfield) Limited | Dewsbury | 1980 |
| Fibregence Ltd | Andover | 2022 |
| Fibreglass Insulations Limited | Sheffield | 2001 |
| Fibrenet Office Services Ltd | York | 2013 |
| Fibrescale Limited | York | 2015 |
| Fibrestone Insulation Products Limited | Lancaster | 2015 |
| Fibrocem Limited | Dalton, Thirsk | 1998 |
| Fibrotex Limited | Cambrdige | 2022 |
| Fica Dacabi Admin Ltd | London | 2020 |
| Ficp Limited | Smalldole | 1998 |
| Fidal Limited | Hornchurch | 2018 |
| Fidel Ernesto Rosales Ulloa Ltd | London | 2021 |
| Fidel Rosales Ltd | London | 2023 |
| Fidelity Absolute Ltd | Torquay | 2026 |
| Fidelity Estates Limited | Droitwich | 2013 |
| Fidelong Garment Co., Ltd | London | 2014 |
| Fidenti Ltd | Sandbach | 2020 |
| Fides Associates Limited | Swaffham | 2014 |
| Fides Domus Ltd | Haverfordwest | 2023 |
| Fides Financial Management Limited | Swaffham | 2023 |
| Fidu Consultancy Limited | Watford | 2019 |
| Fiducia Partners London Limited | London | 2016 |
| Fiduciary Estate Services Ltd. | Manchester | 2026 |