| Flame Fire Tables Limited | Manufacturing | 2017 |
| Flame Fusion Ltd | Hospitality | 2026 |
| Flame Fusion Takeaway Ltd | Hospitality | 2026 |
| Flame Health Associates LLP | | 2011 |
| Flame Healthcare Limited | Administrative & support | 2011 |
| Flame Lily Logistics Ltd | Transport & logistics | 2023 |
| Flame UK Business Services Group Ltd | Professional & scientific | 2015 |
| Flamingo Cleaners Ltd | Other services | 2017 |
| Flamingo Digital Ltd | Professional & scientific | 2019 |
| Flamingo Flats Ltd | Real estate | 2022 |
| Flamingo Legal Services Ltd | Professional & scientific | 2012 |
| Flamsteed Chip Bar Ltd | Wholesale & retail | 2025 |
| Flare Wellbeing & Welfare Ltd | Administrative & support | 2021 |
| Flash Alloys Holdings Limited | Financial services | 2026 |
| Flash Carts Ltd | Wholesale & retail | 2025 |
| Flash Digital Ltd | Professional & scientific | 2023 |
| Flash Hub Ltd | Wholesale & retail | 2026 |
| Flashback Trading Ltd | Water & waste | 2023 |
| Flashdog Films Ltd | Information & communication | 2017 |
| Flasheddierocks Ltd | Information & communication | 2005 |
| Flashing Services (Nottm) Ltd | Construction | 2021 |
| Flashspeed Ltd | Transport & logistics | 2026 |
| Flat CAP Developments Ltd | Construction | 2015 |
| Flatfour Ltd | Real estate | 2014 |
| Flats 1 to 7, the Mill Close Management Company Limited | Households | 2025 |
| Flavia Cafe & Bakery Ltd | Hospitality | 2024 |
| Flavin & Mcghee Limited | Wholesale & retail | 2006 |
| Flavin Group Ltd | Wholesale & retail | 2018 |
| Flavin's Landscapes Ltd. | Administrative & support | 2018 |
| Flavio Maintenance Services Ltd | Construction | 2018 |
| FLAVIU31 Ltd | Hospitality | 2025 |
| Flavor Box Ltd | Hospitality | 2025 |
| Flavor Haven Ltd | Hospitality | 2022 |
| Flavour Expert Limited | Hospitality | 2025 |
| Flavourfuel Foods Ltd | Hospitality | 2025 |
| Flawborough Farms Ltd | Energy | 2023 |
| Flawless Carpet - Upholstery & Floor Care Ltd | Administrative & support | 2025 |
| Flawless Exterior Cleaning & Restoration Ltd | Administrative & support | 2025 |
| Flawless Group Services Ltd | Administrative & support | 2021 |
| Flawless Property Damage Restoration Ltd | Administrative & support | 2025 |
| Flawless Property Preservation Ltd | Administrative & support | 2025 |
| Flaxon Limited | Extraterritorial | 2021 |
| Fledge Bidco Limited | Financial services | 2023 |
| Fledge Midco 1 Limited | Financial services | 2023 |
| Fledge Midco 2 Limited | Financial services | 2023 |
| Fledge Midco 3 Limited | Financial services | 2023 |
| Fledge Topco Limited | Financial services | 2023 |
| Fleek Aesthetics Studio Ltd | Other services | 2021 |
| Fleet Bess Limited | Construction | 2021 |
| FLEET24X7 Limited | Transport & logistics | 2023 |
| Fleetcare Accident Repair Centre Limited | Wholesale & retail | 2008 |
| Fletcher & Co (UK) Limited | Professional & scientific | 2005 |
| Fletcher Churm Ltd | Administrative & support | 2023 |
| Fletcher Construction Consultancy Limited | Construction | 2004 |
| Fletcher Insights Group Ltd | Information & communication | 2026 |
| Fletcher Regency Estates Ltd | Real estate | 2023 |
| Fletchergate Holdings Ltd | Real estate | 2021 |
| Fletchergate Industries Ltd | Hospitality | 2018 |
| Fleurtations Gifts Limited | Wholesale & retail | 2022 |
| Flex Abroad Ltd | Education | 2025 |
| Flexeprint (UK) Limited | Manufacturing | 2006 |
| Flexfab Europe Limited | Manufacturing | 1998 |
| Flexi Direct Services Limited | Manufacturing | 2023 |
| Flexiant Limited | Information & communication | 2019 |
| Flexibenefits Limited | Professional & scientific | 2001 |
| Flexible FD Limited | Information & communication | 2013 |
| Flexigard Limited | Administrative & support | 2010 |
| Flexigas UKC Limited | Professional & scientific | 2015 |
| Flexington Ltd | Information & communication | 2020 |
| Flexopack Limited | Manufacturing | 1987 |
| Flexworks Ltd | Information & communication | 2021 |
| Flexxlens Photo & Video Ltd | Wholesale & retail | 2025 |
| Flexy-Florists Ltd | Manufacturing | 2013 |
| Flexy-Minds Ltd | Health & social care | 2019 |
| FLG Commercial Properties Limited | Real estate | 2021 |
| FLG EOT Limited | Financial services | 2021 |
| FLG Limited | Professional & scientific | 2005 |
| FLG Properties Limited | Households | 2020 |
| Flicks Hair Ltd | Other services | 2026 |
| Flight Club Ltd | Wholesale & retail | 2026 |
| Flight Medic UK Limited | Administrative & support | 2014 |
| Flint Capital Holdings Ltd | Financial services | 2025 |
| Flint Developments (EM) Limited | Real estate | 2022 |
| Flintstones Lets Limited | Real estate | 2023 |
| Flip a Coin Ltd | Wholesale & retail | 2025 |
| Flitterman Investments Limited | Real estate | 1964 |
| Flixtech Electrical Services Limited | Construction | 2021 |
| Fllikyb Services Limited | Hospitality | 2022 |
| Flo-Print (Nottm) Limited | Manufacturing | 2003 |
| FLO4PAWS Ltd | Other services | 2022 |
| Floatdata Limited | Professional & scientific | 1994 |
| Floating Energy Systems Ltd | Professional & scientific | 2008 |
| Flocka Ltd | Information & communication | 2026 |
| Flolets Limited | Real estate | 2021 |
| Flolma Ltd | Real estate | 2017 |
| Flomp Studio Ltd | Manufacturing | 2023 |
| Flood Protection Solutions Limited | Professional & scientific | 2012 |
| Floodfill Software Development Limited | Information & communication | 2021 |
| Floodsaxdirect Limited | Administrative & support | 2012 |
| Flooknal Limited | Wholesale & retail | 1978 |