| Firefly Systems Design Ltd | Information & communication | 2014 |
| Fireforge Solutions Ltd | Information & communication | 2025 |
| Firefork Foods Ltd | Hospitality | 2026 |
| Firenetrix Limited | Wholesale & retail | 2023 |
| Firesafepro Global Limited | Professional & scientific | 2023 |
| Firescript Solutions Ltd | Information & communication | 2025 |
| Firesec Electrical Limited | Construction | 2008 |
| Fireside GAS Heating Ltd | Construction | 2008 |
| Fireside Social Club Ltd | Hospitality | 2025 |
| Firestone UK Limited | Transport & logistics | 1983 |
| Firewalker (UK) Ltd | Arts & recreation | 2005 |
| Fireway Pizza Rugby Ltd | Hospitality | 2025 |
| Fireworks 47 Ltd | Wholesale & retail | 2024 |
| Fireworks Roberto Limited | Wholesale & retail | 2023 |
| Firfield FOX Limited | Real estate | 2018 |
| Firisk Regtech Advisory Limited | Information & communication | 2026 |
| Firliegh Court Management Company Limited | Households | 1994 |
| Firme Recruits Ltd | Administrative & support | 2025 |
| Firmitia Ltd | Wholesale & retail | 2024 |
| Firmpride Limited | Real estate | 2006 |
| Firnam Ltd | Hospitality | 2019 |
| Firoz Enterprise Limited | Hospitality | 2019 |
| Firoz Healthcare Limited | Wholesale & retail | 2023 |
| Firozi Holdings Ltd | Financial services | 2026 |
| Firozi Limited | Professional & scientific | 2025 |
| Firs and Bromford Community Development Trust C.I.C. | Arts & recreation | 2022 |
| Firs Oakmont Holding Limited | Financial services | 2022 |
| Firs Residential Limited | Health & social care | 2022 |
| First 4 Contracts Limited | Construction | 2024 |
| First Academy Foundation | Education | 2013 |
| First Academy Limited | Education | 2011 |
| First Active 365 Homecare Limited | Administrative & support | 2023 |
| First Active 365 Limited | Administrative & support | 2018 |
| First AID One Limited | Professional & scientific | 2014 |
| First Archer Property Management Company Limited | Households | 1991 |
| First Base Employment Staffing Ltd | Administrative & support | 2018 |
| First Base Property Solutions Limited | Real estate | 2019 |
| First Bridge Recruitment Ltd | Administrative & support | 2024 |
| First Build Solutions Limited | Construction | 2020 |
| First Call Movers Limited | Transport & logistics | 2025 |
| First Call Pest Management Ltd | Administrative & support | 2025 |
| First Call Restoration Limited | Construction | 2016 |
| First Call Staff Recruitment Ltd | Administrative & support | 2019 |
| First Care Group Limited | Health & social care | 2017 |
| First Care Healthcare Ltd | Health & social care | 2019 |
| First Castle Developments Limited | Real estate | 1993 |
| First Central Hire Ltd | Administrative & support | 2023 |
| First Choice Builders Birmingham Ltd | Construction | 2023 |
| First Choice Builders Limited | Construction | 2017 |
| First Choice Child Care Limited | Administrative & support | 2009 |
| First Choice Countrywide Ltd | Real estate | 2014 |
| First Choice for Home Improvements Limited | Construction | 2018 |
| First Choice Home Improvements Solihull Limited | Construction | 2018 |
| First Choice Housing & Support Ltd | Health & social care | 2023 |
| First Choice Lettings & Management Ltd | Real estate | 2024 |
| First Choice Logistics Ltd | Transport & logistics | 2013 |
| First Choice Property Centre Limited | Real estate | 2011 |
| First Choice Umrah Limited | Administrative & support | 2025 |
| First City Housing Ltd | Administrative & support | 2023 |
| First Class AID Ltd | Transport & logistics | 2018 |
| First Class Kidz Academy Ltd | Health & social care | 2024 |
| First Class Kitchen Ltd | Hospitality | 2025 |
| First Class Lighting Limited | Wholesale & retail | 2010 |
| First Class Medics Ltd | Health & social care | 2014 |
| First Class School Uniforms Limited | Wholesale & retail | 1995 |
| First Connect Energy Services Ltd | Professional & scientific | 2022 |
| First Connection Limited | Education | 2018 |
| First Connection Services Ltd | Transport & logistics | 2023 |
| First CUT UK Limited | Construction | 2010 |
| First Dental Media Limited | Information & communication | 2002 |
| First DEV Ltd | Information & communication | 2016 |
| First Eco Limited | Administrative & support | 2012 |
| First Editions Limited | Manufacturing | 1994 |
| First Education Centre Limited | Education | 2017 |
| First Floor HS Limited | Other services | 2024 |
| First for Care Limited | Health & social care | 2005 |
| First Frontier Housing Limited | Real estate | 2023 |
| First Frontier Ltd | Arts & recreation | 2020 |
| First Furthest Fastest Limited | Arts & recreation | 2024 |
| First Gymnastics Newcastle Ltd | Arts & recreation | 2024 |
| First Harmony Services Limited | Health & social care | 2015 |
| First Health #1 Limited | Other services | 2020 |
| First Heaven Care Ltd | Health & social care | 2026 |
| First Henderson Court Property Management Company Limited | Households | 1994 |
| First Horizons Care Group Ltd | Health & social care | 2025 |
| First House Associates Limited | Real estate | 2014 |
| First in Facilities Management Limited | Professional & scientific | 2021 |
| First in Future Ltd | Wholesale & retail | 2026 |
| First in Properties Ltd | Real estate | 2026 |
| First in Service Holdings Limited | Construction | 2012 |
| First in Service Limited | Construction | 1966 |
| First Klass Foundation | Administrative & support | 2024 |
| First Klass Shipping Specialist Ltd | Transport & logistics | 2013 |
| First KUT Limited | Other services | 2017 |
| First Lane Consulting Ltd | Professional & scientific | 2023 |
| First Line Housing Ltd | Real estate | 2025 |
| First Link Traders Ltd | Manufacturing | 2022 |
| First Maison Limited | Real estate | 2025 |
| First Mark Limited | Wholesale & retail | 2020 |
| First Mats Limited | Wholesale & retail | 2009 |