| Flexmedics Ltd | Health & social care | 2024 |
| Flexora Edit Ltd | Other services | 2026 |
| Flexpansion Limited | Information & communication | 2008 |
| Flexpro Charging Ltd | Wholesale & retail | 2025 |
| Flexus One Ltd | Wholesale & retail | 2023 |
| Flexwears UK Ltd | Wholesale & retail | 2019 |
| Flexy Angels Limited | Health & social care | 2021 |
| FLF Performance Center Ltd | Arts & recreation | 2014 |
| FLF Training Ltd | Education | 2023 |
| FLG Assured Rents Ltd | Financial services | 2022 |
| Flght Ltd | Information & communication | 2024 |
| FLI Properties Ltd | Construction | 2022 |
| Flick Energy Ltd | Energy | 2017 |
| Flickoo Limited | Information & communication | 2024 |
| Flight Away Ltd | Transport & logistics | 2024 |
| Flight Maintenance Engineering Limited | Information & communication | 1998 |
| Flight Patrol Club Ltd | Administrative & support | 2025 |
| Flight Patrol Limited | Information & communication | 2019 |
| FLIGHT247 Limited | Administrative & support | 2025 |
| Flightaware UK Ltd | Information & communication | 2019 |
| Flightgrabbers Ltd. | Administrative & support | 2011 |
| Flightnews Ltd | Professional & scientific | 2003 |
| Flights Claim Ltd | Professional & scientific | 2015 |
| Flights Hub UK Ltd | Information & communication | 2025 |
| Flights Master UK Ltd | Administrative & support | 2015 |
| Flights on Planet Earth Limited | Extraterritorial | 2020 |
| Flights Spot Limited | Administrative & support | 2025 |
| FLIGHTS365 Limited | Administrative & support | 2025 |
| Flim Group Limited | Professional & scientific | 2015 |
| Flin Facilities Ltd | Administrative & support | 2024 |
| Flin Group Ltd | Financial services | 2025 |
| Flinders Fitness Ltd | Arts & recreation | 2026 |
| Flint Glass Wharf Management Company Limited | Households | 2009 |
| Flint Music Ltd | Information & communication | 2018 |
| Flint Peak Business Advisors Ltd | Extraterritorial | 2026 |
| Flip Flick Limited | Wholesale & retail | 2025 |
| Flip Flop Films (Manchester) Limited | Information & communication | 2020 |
| Flip Flop Property Limited | Real estate | 2022 |
| Flip IT Global Ltd | Administrative & support | 2025 |
| Flip Tech 99 Ltd | Wholesale & retail | 2025 |
| Flip the Script Theatre Company Ltd | Arts & recreation | 2023 |
| Flip&Dip Limited | Hospitality | 2024 |
| Flipbook Films Ltd | Extraterritorial | 2014 |
| Flipbook Limited | Information & communication | 2010 |
| Flipgraceuk Ltd | Wholesale & retail | 2025 |
| Flipmode Limited | Information & communication | 2012 |
| Flipnest Limited | Wholesale & retail | 2025 |
| Flipped Study Limited | Education | 2017 |
| Flipz Limited | Information & communication | 2025 |
| Flipzy Ltd | Wholesale & retail | 2025 |
| Flitch Hand Car Wash Ltd | Administrative & support | 2016 |
| Flix Animation Limited | Information & communication | 2022 |
| Flixbrix Limited | Real estate | 2008 |
| Flixooo Ltd | Wholesale & retail | 2026 |
| Flixton Breakdown and Recovery Services Limited | Transport & logistics | 2017 |
| Flixton Church Management Limited | Professional & scientific | 2013 |
| Flixton Football Club Limited | Arts & recreation | 2025 |
| Flixton Osteopathic Clinic Limited | Health & social care | 2008 |
| Flixx Ltd | Extraterritorial | 2024 |
| FLJ Risk Management Ltd | Professional & scientific | 2023 |
| FLK Minders Limited | Wholesale & retail | 2025 |
| FLM Build Limited | Construction | 2010 |
| FLM Developments Ltd | Construction | 2017 |
| Flmuk Ltd | Health & social care | 2025 |
| FLN Services Ltd | Construction | 2025 |
| FLO Property Consultancy Ltd | Professional & scientific | 2022 |
| Flo-Win Concepts Limited | Wholesale & retail | 2025 |
| Floart Limited | Households | 1993 |
| Float Advance Limited | Financial services | 2026 |
| Float BNB Limited | Hospitality | 2021 |
| Float Glass Industries Limited | Manufacturing | 2017 |
| Float Left Digital Ltd | Other services | 2022 |
| Float Level Ltd. | Health & social care | 2013 |
| Floating Dough Ltd | Hospitality | 2025 |
| Flober Ltd | Construction | 2016 |
| Flock Coffee Van Ltd | Hospitality | 2025 |
| Flock Inns Limited | Hospitality | 2020 |
| Flodave UK Limited | Health & social care | 2021 |
| Floform Limited | Manufacturing | 1959 |
| FLOGIT2 Ltd | Other services | 2013 |
| FLOGIT2US.COM Ltd | Wholesale & retail | 2012 |
| Flohk Ltd | Professional & scientific | 2025 |
| Flojom Ventures Limited | Health & social care | 2013 |
| Flok Ltd | Hospitality | 2016 |
| Flolight Limited | Health & social care | 2015 |
| Flonancie Ltd | Wholesale & retail | 2019 |
| Flood Clothing Co. Ltd | Manufacturing | 2020 |
| Flood Creative Ltd | Professional & scientific | 2014 |
| Flood Estate Limited | Professional & scientific | 2008 |
| Flood for Planning Ltd | Professional & scientific | 2025 |
| Flood Investments Limited | Extraterritorial | 2017 |
| Flood Risk AI Limited | Professional & scientific | 2025 |
| Flood Skirt Ltd | Manufacturing | 2018 |
| Floof Group Limited | Financial services | 2022 |
| Floofo Limited | Manufacturing | 2025 |
| Floor Express Ltd | Wholesale & retail | 2019 |
| Floor Finishes UK Ltd | Construction | 2017 |
| Floor Master Pro Ltd | Construction | 2025 |
| Floor Play Ltd | Construction | 2019 |
| Floor Q Limited | Construction | 2026 |