| First Choice Roofing and Building Solutions Ltd | Construction | 2022 |
| First Choice Settlement Support Services Limited | Health & social care | 2023 |
| First Floor Media Limited | Administrative & support | 2023 |
| First on Scene Medical Ltd | Education | 2021 |
| First Property Holdings Limited | Financial services | 2002 |
| First Recruitment Services Holdings Limited | Administrative & support | 2005 |
| First Recruitment Services Limited | Administrative & support | 1998 |
| First Stop Engineers Ltd | Wholesale & retail | 2003 |
| Firtrees Farm Limited | Real estate | 1954 |
| Fish 77 Limited | Real estate | 2017 |
| Fish Media Group (East) Limited | Extraterritorial | 2009 |
| Fish Media Group (Life Mags) Limited | Information & communication | 2007 |
| Fish Media Group (London) Limited | Extraterritorial | 2007 |
| Fish Media Group Limited | Information & communication | 2006 |
| Fish Street Farm Estate Management Limited | Real estate | 1975 |
| Fisher Barrie Limited | Administrative & support | 2006 |
| Fisher Noah MAK Limited | Professional & scientific | 2020 |
| Fishpool Verulamium Ltd | Real estate | 2021 |
| Fiska Properties Ltd | Real estate | 2025 |
| Fittly Ltd | Administrative & support | 2019 |
| Fitworks Limited | Other services | 2018 |
| Five Star Cleaning Solutions Limited | Other services | 2015 |
| Five to Thirty Nine Hughenden Road (Marshalswick) Management Company Limited | Households | 1972 |
| Fiveacres Country Club Limited | Hospitality | 1958 |
| Fixed 24HR Ltd | Construction | 2025 |
| Fixfloor UK Limited | Construction | 2026 |
| Fixturerose Limited | Professional & scientific | 1983 |
| FJ Construction Limited | Construction | 2015 |
| FJ Digital Ltd | Professional & scientific | 2022 |
| FJD Solutions Ltd | Information & communication | 2018 |
| Flamed Apparel Limited | Wholesale & retail | 2024 |
| Flamstead Property Development Ltd | Construction | 2021 |
| Flamstead Retail Limited | Wholesale & retail | 2024 |
| Flanagan Manufacturing Limited | Manufacturing | 2024 |
| Flashwire Consulting Limited | Information & communication | 2008 |
| Flat-Out Tours Ltd | Arts & recreation | 2026 |
| Flatmak Limited | Construction | 2013 |
| Flawless Beauty by ZOE Ltd | Other services | 2020 |
| Fleckerl Ventures Limited | Professional & scientific | 2019 |
| Fleetcastle Capital Ltd | Financial services | 2023 |
| Fleetville Hairdressing Ltd | Other services | 2024 |
| Fleetville Investments Ltd | Real estate | 2021 |
| Fleetville PO Ltd | Real estate | 2018 |
| Fleva Limited | Wholesale & retail | 2025 |
| Flexible Fabrications Facilities Limited | Administrative & support | 2015 |
| Flexii Studios Ltd | Arts & recreation | 2026 |
| Flextrasonics Limited | Manufacturing | 2013 |
| Flightbites Nutrition Limited | Hospitality | 2025 |
| Flint Homes Limited | Construction | 2015 |
| Flint ROW Limited | Real estate | 2018 |
| Flips Gymnastics Club Limited | Arts & recreation | 2016 |
| Float Labs Limited | Information & communication | 2024 |
| Flola Accountancy Limited | Professional & scientific | 2022 |
| Floodlight Graphics Limited | Manufacturing | 2024 |
| Florida Sorted.Com Limited | Administrative & support | 2023 |
| Florido Limited | Professional & scientific | 2020 |
| Florin Spedition Ltd | Transport & logistics | 2017 |
| Flow Finance Limited | Information & communication | 2023 |
| Flow Right Services (NW) Ltd | Construction | 2017 |
| Flowerbox ST Albans Limited | Wholesale & retail | 2018 |
| Flowspire Ltd | Information & communication | 2024 |
| Fluid Opportunity IV LP | | 2021 |
| Fluid Opportunity V LP | | 2022 |
| FLY Comply International Limited | Other services | 2023 |
| Flyers Grab Hire Ltd | Water & waste | 2017 |
| FM Expert Limited | Construction | 2010 |
| FMC Hospitality Limited | Hospitality | 2020 |
| FMC Services Ltd | Professional & scientific | 2024 |
| Fmcg Gurus Ltd | Extraterritorial | 2015 |
| FNC General LLP | | 2012 |
| Focalglow Limited | Professional & scientific | 2022 |
| Focus Facilities & Engineering Services Ltd | Construction | 2021 |
| Focused Lending Limited | Financial services | 2018 |
| Focusing on Consultants UK Ltd | Professional & scientific | 2011 |
| FOG Services Limited | Administrative & support | 2024 |
| FOM Ltd | Arts & recreation | 2025 |
| Fone Citi Ltd | Wholesale & retail | 2022 |
| Fone-Safe Ltd | Information & communication | 2001 |
| Food Futures Insights Ltd | Professional & scientific | 2019 |
| Foodhall Ventures SPV I LLP | | 2022 |
| FOR Better Health LLP | | 2014 |
| FOR Feather Four Limited | Professional & scientific | 2025 |
| Foragers Property Investment Ltd | Real estate | 2021 |
| Forbes Hall LLP | | 2008 |
| Fordhamav Ltd | Arts & recreation | 2022 |
| Fordingbridge Farm Foods Limited | Wholesale & retail | 2019 |
| Foremost Holdings Limited | Agriculture & fishing | 2017 |
| Forenza (9010) Limited | Real estate | 2021 |
| Forenza (9020) Limited | Real estate | 2021 |
| Forest Town Church Trust | Other services | 2002 |
| Forestflare Ltd | Manufacturing | 2025 |
| Forgotten Parks Foundation | Health & social care | 2016 |
| Forleo Trading Ltd | Financial services | 2023 |
| Form London Consultants Limited | Construction | 2021 |
| Formidable Minds Ltd | Professional & scientific | 2019 |
| Formitrite (Company Formations) Limited | Extraterritorial | 1995 |
| Forrester Trustee Company NO. 1 Limited | Professional & scientific | 2017 |
| Forrester Trustee Company NO. 2 Limited | Professional & scientific | 2017 |
| Forrester Trustee Company NO. 3 Limited | Professional & scientific | 2017 |
| Forrester Trustee Company NO. 4 Limited | Professional & scientific | 2017 |