| Fitch's Service Station Limited | Wholesale & retail | 2005 |
| Fiteasy Ltd | Wholesale & retail | 2024 |
| Fiteria Limited | Wholesale & retail | 2024 |
| Fitness Community Connections CIC | Education | 2023 |
| Fitness Solutions Limited | Construction | 2018 |
| Fitroots Community | Arts & recreation | 2019 |
| Fitroots Limited | Arts & recreation | 2016 |
| Fitshatzi Fitness and Nutrition Ltd | Other services | 2021 |
| Fitworth Limited | Wholesale & retail | 2023 |
| Fitzrovialofts Property Maintenance Ltd | Construction | 2024 |
| Fiuniverse Ltd | Wholesale & retail | 2023 |
| Five a Day Ltd | Wholesale & retail | 2018 |
| Five Akhis Slough Ltd | Hospitality | 2025 |
| Five K Property Limited | Real estate | 2018 |
| Five Rivers Distribution Ltd | Wholesale & retail | 2020 |
| Five Rivers Estates Limited | Real estate | 2022 |
| Five Rivers Transportation Ltd | Transport & logistics | 2024 |
| Five Rivers Trucking Ltd | Transport & logistics | 2019 |
| Five Star Kitchen & Bedroom Ltd | Other services | 2019 |
| Five Star Nails (UK) Limited | Other services | 2014 |
| FIVE12 Services Ltd | Professional & scientific | 2024 |
| Fivor Construction Ltd | Construction | 2019 |
| FIX & Solve Ltd | Wholesale & retail | 2026 |
| FIX a Flame Ltd | Construction | 2026 |
| Fixnow IT Ltd | Information & communication | 2020 |
| Fixon & Bailey Ltd | Energy | 2024 |
| Fizit Limited | Information & communication | 2022 |
| Fiztech Ltd | Wholesale & retail | 2025 |
| Fizz Online Seller Ltd | Wholesale & retail | 2025 |
| FK Services Operations Limited | Administrative & support | 2025 |
| Flagut Healthcare Connections Ltd | Health & social care | 2012 |
| Flame House UK Limited | Hospitality | 2024 |
| Flamehousegrill Limited | Hospitality | 2025 |
| Flameworks Frimley Ltd | Wholesale & retail | 2026 |
| Flameyard Ltd | Hospitality | 2026 |
| Flash Cargo Ltd | Transport & logistics | 2022 |
| Flash Fibre & Data Solutions Ltd | Information & communication | 2022 |
| Flashflow Plumbing Limited | Construction | 2026 |
| Flat Back Stunts Limited | Arts & recreation | 2021 |
| Flat White Agency Ltd | Professional & scientific | 2022 |
| Flatam Properties Ltd | Real estate | 2016 |
| Flatdor Consultancy Services Ltd | Professional & scientific | 2017 |
| Flavour Buddy Ltd | Manufacturing | 2025 |
| Flavour Dash Ltd | Manufacturing | 2011 |
| Flavour FIX Slough Ltd | Hospitality | 2025 |
| Fleet and Auto Worx London Ltd Ltd | Wholesale & retail | 2026 |
| Fleet Valley Care Limited | Health & social care | 2019 |
| Fleetwood AA Limited | Construction | 2020 |
| Fleetwood Architectural Aluminium Limited | Construction | 1997 |
| Flex Cabs Ltd | Transport & logistics | 2025 |
| Flex Consultants Limited | Information & communication | 2010 |
| Flex Supplements Ltd | Wholesale & retail | 2025 |
| Flex Utilities Limited | Transport & logistics | 2004 |
| Flex Value Ltd | Wholesale & retail | 2020 |
| Flexcrete Technologies Limited | Manufacturing | 2005 |
| Flexforward Limited | Other services | 2020 |
| Flexi Healthcare Services Limited | Health & social care | 2020 |
| Flexibox International Limited | Manufacturing | 1945 |
| Flexidata Limited | Information & communication | 2017 |
| Flexii-Childcare Ltd | Health & social care | 2020 |
| Flexiphone Ltd | Wholesale & retail | 2025 |
| Flexton Developments Limited | Real estate | 2014 |
| Flexxora Global Ltd | Wholesale & retail | 2025 |
| Flight Kingdom Limited | Administrative & support | 2014 |
| Flight Surveys Limited | Professional & scientific | 2024 |
| Flightpath Storage Limited | Other services | 2025 |
| Flightpath Travel Ltd | Administrative & support | 2023 |
| Flip Stone Ltd | Wholesale & retail | 2026 |
| Fliptank Limited | Real estate | 2024 |
| Flipzo.Storee Ltd | Wholesale & retail | 2026 |
| Flocky Ltd | Wholesale & retail | 2024 |
| Flomat-Care LMT Limited | Health & social care | 2014 |
| Floor the Room Ltd | Construction | 2024 |
| Floorinn Limited | Wholesale & retail | 2024 |
| Flora Orthodontics Ltd | Manufacturing | 2014 |
| Flora TEC Solutions Limited | Construction | 2022 |
| Florian O Sales Ltd | Wholesale & retail | 2025 |
| Florida Trans Ltd | Transport & logistics | 2016 |
| Floryn House Care Limited | Health & social care | 2022 |
| Flow Formula Limited | Wholesale & retail | 2025 |
| Flowers by Lorand Limited | Wholesale & retail | 2016 |
| Flowsys Associate Ltd | Professional & scientific | 2022 |
| Fluffy Spuds Ltd | Hospitality | 2025 |
| Flus Limited | Transport & logistics | 2018 |
| Flux Estates Limited | Real estate | 2024 |
| FLY Hawk Luggage Limited | Wholesale & retail | 2024 |
| FLY Lifts NO1 Limited | Professional & scientific | 2024 |
| FLY Universal Ltd | Administrative & support | 2023 |
| Flyaway Ltd | Administrative & support | 2019 |
| Flying Bird Logistics Ltd | Transport & logistics | 2016 |
| Flying Blue Horse Ltd | Real estate | 2023 |
| Flylink Services Ltd | Transport & logistics | 2010 |
| Flynn Fire Limited | Public administration | 2020 |
| Flyout With Da'Mos Travel Limited | Professional & scientific | 2024 |
| Flyt by Arabian Nights Travel & Tourism Ltd | Administrative & support | 2021 |
| FM Education Services Limited | Other services | 2009 |
| Fmchets Ltd | Health & social care | 2024 |
| FMO Investments Ltd | Real estate | 2026 |
| Fmoti Ltd | Transport & logistics | 2019 |
| FMP HR and Payroll Software Limited | Professional & scientific | 2015 |