| Focus Networks Limited | Information & communication | 1999 |
| Focus Oxford Risk Management Ltd | Extraterritorial | 2025 |
| Focus Physiotherapy and Ergonomics Limited | Health & social care | 2005 |
| Focus Surveying Services Ltd | Professional & scientific | 2007 |
| Focusrite Audio Engineering Limited | Manufacturing | 1989 |
| Focusrite Group Emea Limited | Wholesale & retail | 2023 |
| Focusrite PLC | Manufacturing | 2014 |
| Fogbow Services Ltd | Wholesale & retail | 2025 |
| Folex Motorhouse Ltd | Wholesale & retail | 2026 |
| Folly Farm Solar Power Limited | Energy | 2015 |
| Folly Records Limited | Information & communication | 2007 |
| Follyfoot Healing With Horses CIC | Health & social care | 2013 |
| Fomo Drinks Ltd | Manufacturing | 2025 |
| Fone Tech Communication Ltd | Information & communication | 2006 |
| Fonegogo Ltd | Wholesale & retail | 2025 |
| Fonex Ltd | Information & communication | 2008 |
| Fontwood Limited | Real estate | 1987 |
| Food Direct Limited | Wholesale & retail | 2020 |
| Food for Life Limited | Manufacturing | 2017 |
| Foodbox Grill Ltd | Hospitality | 2026 |
| Foodservice Support Limited | Professional & scientific | 2009 |
| Foot First Solutions Ltd | Health & social care | 2020 |
| Football Warehouse UK Ltd | Education | 2025 |
| Footyworld Tech Ltd | Information & communication | 2024 |
| FOR the Love of Adhd Limited | Health & social care | 2025 |
| For-Site Labour Limited | Construction | 2005 |
| Forbes Education Recruitment Ltd | Administrative & support | 2023 |
| Forbowes Ltd | Administrative & support | 2016 |
| Forculus Security Services Ltd | Administrative & support | 2021 |
| Ford & Partners Lettings (High Wycombe) Ltd | Real estate | 2020 |
| Ford & Partners Ltd | Real estate | 2019 |
| Ford View Management Company Limited | Households | 2008 |
| Fordbridge Enterprise Ltd | Information & communication | 2024 |
| Foreden Solutions Ltd | Information & communication | 2018 |
| Foremost Cycling Ltd | Wholesale & retail | 2017 |
| Foremost Golf Limited | Wholesale & retail | 1984 |
| Foresight Media Services Ltd | Information & communication | 2020 |
| Foresight Plus Ltd | Extraterritorial | 2015 |
| Foress Ltd | Professional & scientific | 2020 |
| Forest Healthcare Services Ltd | Administrative & support | 2026 |
| Forestview Windows Limited | Construction | 2023 |
| Forfacesakelondon Ltd | Other services | 2021 |
| Forge Fitness (Kingsey) Ltd | Arts & recreation | 2026 |
| Forge Recycling (Holdings) Limited | Financial services | 2017 |
| Forge Recycling (UK) Limited | Water & waste | 2010 |
| Forge Waste Limited | Extraterritorial | 2002 |
| Fork and Feast Catering & Events Ltd | Hospitality | 2024 |
| Form & Finish Fit-Out Ltd | Construction | 2025 |
| Formeasy Limited | Information & communication | 1993 |
| Forster Finance Limited | Administrative & support | 2025 |
| Fort Phoenix Limited | Arts & recreation | 2019 |
| Fortis Global Solutions Ltd | Wholesale & retail | 2015 |
| Forty Four Partners Limited | Hospitality | 2025 |
| Forward Accounting Services Limited | Professional & scientific | 2025 |
| Forza Autofficina Limited | Wholesale & retail | 2025 |
| Fosse Films Ltd | Information & communication | 2009 |
| Foster & Gane Limited | Wholesale & retail | 2012 |
| Founderz UK Limited | Administrative & support | 2025 |
| Foundry Court Block B Slough RTM Company Ltd | Households | 2026 |
| Foundry Court Slough Block a RTM Company Ltd | Households | 2025 |
| Fountain and Caine Limited | Construction | 2005 |
| Fountain Court Management Company (Berkshire) Limited | Households | 2014 |
| Four Four Consultancy Limited | Information & communication | 2010 |
| Four Paws Pantry Ltd | Wholesale & retail | 2026 |
| Four Seasons Vehicle Hire Ltd | Administrative & support | 2026 |
| Fouracre Management Company Limited | Real estate | 2022 |
| Fourtold Holdings Limited | Financial services | 2018 |
| Fourtold Ltd | Professional & scientific | 2013 |
| FOX Cover Maintenance Limited | Other services | 2025 |
| FOX Hollow Limited | Construction | 2003 |
| FOX Pioneer Centre Limited | Education | 2020 |
| Foxglove Studio Ltd | Wholesale & retail | 2017 |
| Foxx Designs Ltd | Professional & scientific | 2014 |
| FQ Property Management Ltd | Households | 2025 |
| FR Auto Solutions Ltd | Wholesale & retail | 2023 |
| Fr'Um Dark BUT Fr'Iendly Limited | Wholesale & retail | 2024 |
| Fractalia Limited | Administrative & support | 2005 |
| Frajo Limited | Information & communication | 2013 |
| Frame Crew Ltd | Wholesale & retail | 2025 |
| Framptons Management Limited | Real estate | 2014 |
| Francesca Saffari Ltd | Information & communication | 2022 |
| Francisco Construction Ltd | Construction | 2017 |
| Frank Adams Legacy Limited | Real estate | 2011 |
| Frank Day Upholstery Limited | Manufacturing | 2011 |
| Frank Goddard & SON Limited | Real estate | 2003 |
| Franklin Facilities Limited | Extraterritorial | 2022 |
| Frankmark Brickwork & Construction Limited | Construction | 2018 |
| Frarg Ltd | Information & communication | 2025 |
| Fraser Jones Ltd | Real estate | 2026 |
| Freakydemon Racing Limited | Manufacturing | 2014 |
| Freckle Design Ltd | Professional & scientific | 2023 |
| Frederick House Group Ltd | Real estate | 2026 |
| Fredrick International Foundation Ltd | Administrative & support | 2022 |
| Freebord UK Limited | Wholesale & retail | 2007 |
| Freedom & Life Ltd | Professional & scientific | 2021 |
| Freedom and Life the Label Ltd | Wholesale & retail | 2024 |
| Freespirit Events Ltd | Hospitality | 2022 |
| Freespirit PUB Company Ltd | Hospitality | 2019 |
| Freespirit Recruitment Ltd | Administrative & support | 2022 |
| Freestone Groundworks Ltd | Construction | 2023 |