| Firechecked Limited | Reigate | 2025 |
| Fireclass Ltd | Wantage | 2020 |
| Firecom Limited | Grimsby | 2016 |
| Firecom Systems Limited | Nottingham | 2006 |
| Firecon Limited | Altrincham | 2023 |
| Fireconsultancydarling Ltd | London | 2026 |
| Firecrest Services Limited | Gravesend | 2026 |
| Firecrest UK Ltd | Mansfield | 2004 |
| Firedon Ltd. | Borehamwood | 2007 |
| Firedoor IQ Ltd | Epping | 2026 |
| Fireflux Ltd | Lichfield | 2017 |
| Fireguard Safety Ltd | London | 2025 |
| Firegy Ltd | Salford | 2023 |
| Firehaven Safety Ltd | Tunbridge Wells | 2025 |
| Fireholt FP Limited | Doncaster | 2024 |
| Firelink Protection Limited | Glasgow | 2017 |
| Firemed Events Limited | Gravesend | 2019 |
| Firenet International Limited | Camberley | 2015 |
| Firenet Security Ltd | Solihull | 2019 |
| Firenza Fire Prevention Limited | Fareham | 2026 |
| Firepoint Scotland Limited | Motherwell | 1987 |
| Firepro BG Ltd | Surbiton | 2026 |
| Firepro Connect Ltd | London | 2026 |
| Firepro Safety Ltd | Rugby | 2019 |
| Fireprodac Ltd | Hornchurch | 2025 |
| Fireprotectservicesuk Limited | Brentwood | 2020 |
| Fireqa Limited | Polegate | 2020 |
| Fireriskassessors Ltd | Harlow | 2017 |
| Firerox Protection Ltd | London | 2018 |
| Firesafe Assessment Scotland Ltd | Glasgow | 2026 |
| Firesafe Consultancy Limited | Fife | 2003 |
| Firesafe Operations UK Ltd. | Coulsdon | 2014 |
| Firesafe Services (North East) Limited | Sheffield | 2009 |
| FIRESAFETY4U Ltd | Stevenage | 2021 |
| Firescape Risk Advisory Ltd | Sevenoaks | 2023 |
| Firesecuresolutions Limited | Leeds | 2024 |
| Fireset Ltd | Benfleet | 2025 |
| Fireshield Fire Protection Limited | Radstock | 1998 |
| Fireshield Safety Ltd | Glasgow | 2025 |
| Fireshield Technologies Ltd | London | 2019 |
| Firesmarter Limited | Manchester | 2016 |
| Firesnuff Limited | Hemingford Grey | 2017 |
| Firesolve Limited | Skelmanthorpe Huddersfield | 1997 |
| Firestop Services Limited | High Wycombe | 2003 |
| Firestop Technologies Ltd | Milton Keynes | 2025 |
| Firestopsouthwest Ltd | Bristol | 2025 |
| Firesurv Ltd | Nottingham | 2019 |
| Firetec Services Limited | Sidcup | 2017 |
| Firetech Sprinklers Limited | Bolton | 2025 |
| Fireteknical Ltd | Wallasey Wirral | 2023 |
| Firewall Passive Fire Protection Ltd | Hull | 2024 |
| Firewatch Fire Protection Ltd | Durham | 2016 |
| Firewatch South West Limited | Sowerby Bridge | 1997 |
| Firewise Business Solutions Limited | Portchester, Fareham | 2017 |
| Firewise Ltd | Glasgow | 2013 |
| Firewiseuk Limited | Penkridge | 2021 |
| Firex Ltd | Londonderry | 2024 |
| Firexo Distribution Limited | Beaconsfield | 2021 |
| Firexo Limited | London | 2019 |
| Firexo Motorsport Limited | Beaconsfield | 2020 |
| Firexpo Ltd | Chatham | 2025 |
| Firis Group Ltd | Burton Upon Trent | 2026 |
| Firm Steps Limited | Corby | 2026 |
| Firmare Limited | Leyland | 2025 |
| First 4 Fire Ltd | Southampton | 2003 |
| First 4 Fire Safety & Servicing Limited | Teignmouth | 2023 |
| First 4 Solutions Ltd | London | 2025 |
| First AID Forms Ltd | Fenstanton | 2020 |
| First AID Provision Limited | London | 2022 |
| First AID Schools Ltd | Doncaster | 2022 |
| First Call Medical Solutions Ltd | Blackpool | 2025 |
| First Choice Carers Ltd | Uxbridge | 2021 |
| First Choice Medical Services Limited | Bridlington | 2020 |
| First Class Healthcare Ltd | Chatham | 2009 |
| First Class Healthy Solutions Limited | Wigston | 2021 |
| First Class Hygiene Suppliers Ltd | Manchester | 2025 |
| First Direct Training Ltd | Dagenham | 2010 |
| First for Safety Oxon Limited | Chipping Norton | 2026 |
| First Line Fire Services Ltd | Berkhamsted | 2023 |
| First Line Medical Ltd | Northampton | 2021 |
| First Real Solutions Ltd | Leicester | 2018 |
| First Response First AID Training and Events Ltd | Clacton-On-Sea | 2020 |
| First Response Safety Group Ltd | London | 2026 |
| First Shout Fire Safety Management Limited | Northallerton | 2023 |
| First Stop Health Care Limited | Manchester | 2023 |
| First Take Safety Ltd | Belfast | 2020 |
| First Years First AID Limited | Broadstone | 2026 |
| Firstclass Safety and Control Ltd | Colchester | 2017 |
| Firstinfirecompliance Limited | Burnley | 2025 |
| Firstlinehealthgroup Limited | Rochford | 2023 |
| Fishguard and Goodwick Development CIC | Goodwick | 2024 |
| Fistfinance Ltd | London | 2025 |
| Fitfirestop Limited | Sunbury-On-Thames | 2019 |
| Fitness 4 Kids Ltd | London | 2023 |
| Fitness 4 Kidz C.I.C. | London | 2023 |
| Fitz Fire & Security Limited | Benfleet | 2022 |
| Fitzalanirvineconsultants Limited | Littlehampton | 2025 |
| Fitzpatrick Healthcare Ltd | Huntingdon | 2024 |
| Fitzwilliam International Consultants Limited | Sawston | 2017 |
| Five Alley Consulting Ltd | London | 2024 |