| Filey Property Ltd | Real estate | 2023 |
| Filika Theydon Bois Ltd | Hospitality | 2022 |
| Filipinas Limited | Health & social care | 2025 |
| Fillebrook Hall Estate Co., Limited | Real estate | 1957 |
| Film Facilities Limited | Administrative & support | 2022 |
| Film Quest Ltd | Other services | 1994 |
| Filmusicompany Ltd | Arts & recreation | 2020 |
| Finance and Systems Department Ltd | Professional & scientific | 1998 |
| Financial Education Academy Ltd | Education | 2024 |
| Finchley RTM Company Limited | Real estate | 2006 |
| Findabis Ltd | Information & communication | 2025 |
| Findwedge Limited | Wholesale & retail | 1988 |
| Finestkind Consulting Limited | Professional & scientific | 2006 |
| Finforex Ltd | Financial services | 2006 |
| Finnet Limited | Information & communication | 2000 |
| Finsbury Network Contracts Limited | Information & communication | 1995 |
| Fiona M Ashworth Limited | Professional & scientific | 2015 |
| Fiora London Ltd | Professional & scientific | 2025 |
| Firat Altindag Ltd | Wholesale & retail | 2024 |
| Fire King Limited | Wholesale & retail | 2013 |
| Fire of Anatolian Ltd | Hospitality | 2026 |
| Fireaway Pizza Barkingside 2 Ltd | Hospitality | 2025 |
| Firebush Limited | Hospitality | 2017 |
| First Abbey Limited | Financial services | 1998 |
| First ACT London LLP | | 2020 |
| First AID Limited | Administrative & support | 1987 |
| First Aider Ltd | Education | 2007 |
| First Approach Limited | Information & communication | 1999 |
| First Choice Scaffolding (Essex) Ltd | Construction | 2021 |
| First Choice Solutions Ltd | Administrative & support | 2025 |
| First Class Financial Limited | Financial services | 2004 |
| First Consultancy (UK) Limited | Information & communication | 2002 |
| First Flight Holdings EOT Limited | Administrative & support | 2024 |
| First Flight Holdings Ltd | Transport & logistics | 2023 |
| First Hand Records Limited | Information & communication | 2007 |
| First Impressions Maintenance Services Limited | Professional & scientific | 1981 |
| First Select Insurance Services Limited | Financial services | 1987 |
| First Source Tech Ltd | Information & communication | 2022 |
| First Stop Signs Print Ltd | Manufacturing | 2023 |
| Firstbase (Future Marketing) Holding Limited | Financial services | 2024 |
| Firstbase (Future Marketing) Services Limited | Administrative & support | 2024 |
| Fiscal Management UK Limited | Professional & scientific | 2003 |
| Fisco Tools Limited | Manufacturing | 1963 |
| Fish & Chips Saffron Walden Ltd | Hospitality | 2026 |
| Fish Property (UK) Limited | Construction | 2000 |
| Fisher & Newman Limited | Construction | 2003 |
| Fisl Training Consultancy Limited | Education | 2011 |
| Fit and Fusion Ltd | Information & communication | 2025 |
| Fit Pro Sales Academy Ltd | Education | 2022 |
| Fitch Contractors Limited | Construction | 2006 |
| Fitchlea PS Limited | Construction | 2025 |
| Fitkidz 4EVER Limited | Arts & recreation | 2003 |
| Fitzroy Place (Blackmore) Limited | Households | 2024 |
| Five Stacks Residential Home Limited | Health & social care | 2005 |
| Fivestar Catering Ltd | Hospitality | 1999 |
| Fiveways Pagaota Limited | Wholesale & retail | 2023 |
| FIX Phones Limited | Wholesale & retail | 2022 |
| Fixedfast Limited | Construction | 2007 |
| FK Ecom Ltd | Wholesale & retail | 2024 |
| FKA Lofts Ltd | Construction | 2022 |
| FKB Commerce Ltd | Wholesale & retail | 2026 |
| Flakt Woods Limited | Manufacturing | 1928 |
| Flaming Wood Ltd | Construction | 2019 |
| Fleet Fabrications Limited | Real estate | 1985 |
| Fleetarch Ltd | Professional & scientific | 2007 |
| Flexbuild Limited | | 1990 |
| Flightspedia Ltd | Administrative & support | 2021 |
| Flint Cottages Management Company Limited | Real estate | 2000 |
| Flipora Ltd | Wholesale & retail | 2025 |
| Flock Container Services Limited | Construction | 2002 |
| Flomax UK Limited | Wholesale & retail | 2003 |
| Floorlayers Limited | Wholesale & retail | 1990 |
| Floortex Carpet Ltd | Wholesale & retail | 2025 |
| Florentin Fonche Foundation | Education | 2005 |
| Florey Investments Limited | Real estate | 1956 |
| Florin Building Solutions Limited | Construction | 2005 |
| Flouren Ltd | Professional & scientific | 2025 |
| Flowify Heating Ltd | Construction | 2022 |
| Flowtra Consulting Limited | Professional & scientific | 2026 |
| Fluxenor Limited | Wholesale & retail | 2024 |
| FLY Deal Fare Limited | Administrative & support | 2025 |
| Folaforfameworld Ltd | Information & communication | 2025 |
| Followflow Software Limited | Information & communication | 2026 |
| Ford Place Holdings Limited | | 1984 |
| Fordrill Limited | Mining & quarrying | 1996 |
| Foresite Financial Limited | Financial services | 2002 |
| Forest Hose & Hydraulics Limited | Manufacturing | 2000 |
| Forest View Property Management Company Limited | Households | 2021 |
| Former Glory (Essex) Limited | Administrative & support | 2003 |
| Formweb Limited | Information & communication | 2006 |
| Fortified Wellness Community Interest Company | Manufacturing | 2026 |
| Fortis-Pro Consulting Limited | Health & social care | 2024 |
| Fortrix Limited | Other services | 2000 |
| Forwards & Upwards Limited | Financial services | 2006 |
| Foskett Marr Gadsby & Head LLP | | 2007 |
| Found & Cherished Ltd | Wholesale & retail | 2024 |
| Foundations Sales & Letting Ltd | Other services | 2017 |
| Four Angels Properties Ltd | Real estate | 2016 |
| Four Bright Marketing Limited | Wholesale & retail | 2021 |
| Four S Developments Limited | Construction | 2006 |