| Finxed Limited | London | 2014 |
| Finyard Limited | Ilford | 2019 |
| Finzo Accountants Ltd | Harrow | 2020 |
| Finzuler Ltd | Bristol | 2008 |
| Fiomic Ltd | London | 2024 |
| Fiona Sheward Ltd | Tunbridge Wells | 2010 |
| Fiore-Uk Limited | Nr Coventry | 2013 |
| Fiorente Property Sourcing Ltd | Birmingham | 2019 |
| Fioretti Ltd | Banningham | 2018 |
| FIR Lane 1964 Limited | Oldham | 2014 |
| Firaly Ltd | London | 2025 |
| Firas Limited | London | 1995 |
| Firby Investments Limited | Bedale | 2010 |
| Fircoombe Hall Limited | Manchester | 2016 |
| Fire & Rescue Training Ltd | Telford | 2003 |
| Fire & Security Apps Ltd | Alderley Edge | 2013 |
| Fire & Security Limited | Crawley | 1998 |
| Fire Alert Security Technology UK Limited | England | 2019 |
| Fire and Fitness Consultancy Ltd | Colne | 2015 |
| Fire and Security Risk Assessments Limited | Tadworth | 2017 |
| Fire and Water Risk Solutions Ltd | Stockport | 2025 |
| Fire Barrier Systems Limited | Coventry | 2014 |
| Fire Barriers Automotive Limited | Coventry | 2014 |
| Fire Certification UK Limited | Cheadle | 2019 |
| Fire Curtain Corporation Limited | Penarth | 2009 |
| Fire Depot Ltd | Oakham | 2020 |
| Fire Detection Shop Limited | Derby | 2020 |
| Fire Door Services Limited | Bracknell | 2008 |
| Fire Doors Plus Ltd | Dereham | 2013 |
| Fire Dynamics Ltd | London | 2019 |
| Fire Hosetech (Holdings) Limited | Settle | 2013 |
| Fire Installation Specialists Ltd | Maidstone | 2018 |
| Fire PAL Limited | London | 2015 |
| Fire Prevention Plus Ltd | Dereham | 2017 |
| Fire Proof Solutions Limited | Crowborough | 2020 |
| Fire Protective Coatings (UK) Limited | Carlisle | 2000 |
| Fire Risk Assessments Employee Trustee Limited | Nottingham | 2023 |
| Fire Safe Security Limited | Redditch | 2012 |
| Fire Safety Advisors Ltd | Holt | 2021 |
| Fire Safety Group Limited | Caerphilly | 2016 |
| Fire Safety Store Limited | Derby | 2020 |
| Fire Save Limited | Northampton | 2000 |
| Fire Suppression International Limited | Avonmouth | 2017 |
| Fire Suppression Maintenance Limited | Swindon | 2013 |
| Fire Suppression Systems Limited | Swindon | 2013 |
| Firebird Topco Ltd | London | 2024 |
| Firecat Ltd. | Bracknell | 2012 |
| Firecracker Moto Limited | Lamberhurst | 2022 |
| Fired UP Group Limited | West Yorkshire | 2007 |
| Firedoor Experts Limited | Hatfield | 2017 |
| Firefly Office Supplies Limited | Southampton | 2006 |
| Firefly Protection Systems Limited | Knutsford | 2025 |
| Firefly U.K Ltd | Knutsford | 2025 |
| Firefox Electrical Services Ltd | Norwich | 2013 |
| Firefox Limited | Barnet | 2009 |
| Firemark Extinguishers Limited | Bridgwater | 1991 |
| Firemed UK Ltd | Belvedere | 2014 |
| Fireplace World (UK) Limited | Huddersfield | 2003 |
| Firesafety.Uk.Com Limited | Derby | 2020 |
| Fireshore Limited | Port Talbot | 2011 |
| Firestop Systems Limited | Huddersfield | 2009 |
| Firestrike IP Ltd | Billericay | 2016 |
| Firethorn Limited | London | 2025 |
| Fireworks R US Ltd | Nelson | 2018 |
| Firezone Limited | Seaford | 2009 |
| Firgo Barn Limited | Salisbury | 2008 |
| Firgrove Care Home Limited | London | 2003 |
| Firinci Oglu Foodstuff Trading Ltd | Harrogate | 2022 |
| Firlands Residents Association Limited | Haywards Heath | 2009 |
| Firm Advice Limited | London | 1984 |
| Firma Egentligen Invest Limited | London | 2020 |
| Firma Egentligen Limited | London | 2020 |
| Firma JAN Sandin Limited | London | 2009 |
| Firma Services Europe Limited | London | 2013 |
| Firmager Funeral Service Limited | Nottingham | 2000 |
| Firman Glass Limited | Romford | 2010 |
| Firmenich Wellingborough Pension Trustee Limited | Middlesex | 2021 |
| Firmount Estate Management Limited | Ballyclare | 1997 |
| Firmount Housing Management Limited | Ballyclare | 1997 |
| Firoma Holdings Limited | Coventry | 2025 |
| Firs Chase 1959 Limited | Colchester | 2014 |
| Firs Lane Management Company NO.1 Limited | Warrington | 2007 |
| Firs Lane Management Company NO.2 Limited | Warrington | 2007 |
| Firs Lane Management Company NO.3 Limited | Warrington | 2007 |
| Firsd International Co., Ltd | Beckenham | 2014 |
| First 4 Education (UK) Limited | Melton Mowbray | 2011 |
| First 4 Feet Ltd | Horsham | 2025 |
| First 4 Frames Limited | Grangemouth | 2014 |
| First 4 Service Group Limited | Manchester | 2021 |
| First Acacia Limited | Wisbech | 2017 |
| First Advisor Limited | Hertford | 2014 |
| First AID Essentials Ltd | Balham | 2011 |
| First AID for Life London Ltd | Balham | 2011 |
| First AID for Pets Ltd | London | 2016 |
| First AID Medical Services Limited | London | 2023 |
| First AID Plumbing & Heating Ltd | Nuneaton | 2011 |
| First and Last Management Company Limited | Exeter | 2016 |
| First Andover Limited | Manchester | 2016 |
| First Angels Healthcare Limited | Leeds | 2016 |
| First Ascent Limited | Bangor | 2010 |