| Fineen Limited | Real estate | 1995 |
| Finex Incons Ltd | Construction | 2019 |
| Finial Group Ltd | Professional & scientific | 2025 |
| Finite Element Analysis Limited | Information & communication | 1977 |
| Finoptix Ltd | Information & communication | 2018 |
| FIR Croft Consultancy Ltd | Real estate | 2009 |
| Fire Door Closers Limited | Wholesale & retail | 2014 |
| Fire Systems Limited | Construction | 1991 |
| Fire Systems Property Limited | Real estate | 2024 |
| Firefirstuk Limited | Construction | 2008 |
| Firestone Creative Limited | Professional & scientific | 2017 |
| Firetap Ltd | Administrative & support | 2016 |
| Firmbase Drives Ltd | Construction | 2025 |
| First Call Contract Services Limited | Administrative & support | 1996 |
| First Care Choice Ltd | Health & social care | 2019 |
| First Coins Pawn LLP | | 2008 |
| First Digital Intelligence Ltd | Information & communication | 2022 |
| First Take Autocue Limited | Information & communication | 2012 |
| Firstword Investments Ltd | Administrative & support | 2021 |
| Fit for the TIP Limited | Water & waste | 2026 |
| Five Islands Consulting Ltd | Information & communication | 2024 |
| Fivetwelve Marketing Limited | Professional & scientific | 2023 |
| FIX This Build That Ltd | Construction | 2018 |
| Fixbolt Limited | Construction | 2025 |
| Fixer FOX Ltd | Construction | 2026 |
| Fizzarchi Limited | Professional & scientific | 2017 |
| Flando Limited | Professional & scientific | 2013 |
| Flare Path Financial Services Limited | Professional & scientific | 2013 |
| Flat-Out Creative Solutions Ltd | Information & communication | 2014 |
| Flats Investment Ltd | Real estate | 2020 |
| Fletcher Crane Architects Limited | Professional & scientific | 2009 |
| Fletcher-Raymond Limited | Arts & recreation | 1996 |
| Fleximarketing Investments Limited | Financial services | 2026 |
| Fleximarketing Solutions Ltd | Professional & scientific | 2024 |
| Flight Bars Ltd | Hospitality | 2025 |
| Flinders Ltd | Professional & scientific | 2022 |
| Flor Fria Taqueria Ltd | Hospitality | 2024 |
| Flora and FIX Ltd | Administrative & support | 2025 |
| Flora MAC Donald Associates Limited | Administrative & support | 2017 |
| Florida Energy Limited | Energy | 2019 |
| Flow Assured Limited | Professional & scientific | 2011 |
| Flowercloud Limited | Financial services | 2016 |
| Flowinvesting Ltd | Real estate | 2020 |
| Flowlead Limited | Professional & scientific | 2015 |
| FLS7 Ltd | Hospitality | 2025 |
| Fluid Technologies (Environmental) Limited | Professional & scientific | 1991 |
| Fluxx Digital Ltd | Professional & scientific | 2024 |
| Flydoc Limited | Administrative & support | 2010 |
| FMN Limited | Arts & recreation | 2020 |
| FN Trading Ltd | Education | 2019 |
| Focus Analytics Ltd | Information & communication | 2022 |
| Foden Bell Limited | Information & communication | 2013 |
| Foggo Associates Limited | Professional & scientific | 1992 |
| Foki Limited | Information & communication | 2022 |
| Folders Keep (Burgess Hill) Management Limited | Households | 2007 |
| Follett & Co Limited | Professional & scientific | 2012 |
| Follow the Consumer Ltd | Professional & scientific | 2018 |
| Following Focus Ltd | Professional & scientific | 2024 |
| Fone Gadgets & Accessories Ltd | Wholesale & retail | 2014 |
| Fone N Vape Stuff Ltd | Manufacturing | 2025 |
| Fontana Soccer Coaching Ltd | Education | 2017 |
| Fonteze Limited | Information & communication | 2021 |
| Foodally Ltd | Wholesale & retail | 2018 |
| Foox Ltd | Information & communication | 2026 |
| FOR YOU Wain Ltd | Wholesale & retail | 2023 |
| Force TEN Ltd | Construction | 2020 |
| Foreshank Redemption Limited | Wholesale & retail | 2025 |
| Forest Berry Limited | Wholesale & retail | 2020 |
| Forest Court (Egham) Management Limited | Households | 1981 |
| Forest Enterprise Limited | Hospitality | 2020 |
| Forest Schooling UK CIC | Education | 2022 |
| Forgate Secretaries Limited | Administrative & support | 2001 |
| Forge Capital Limited | Real estate | 2016 |
| Form Design Group Ltd | Professional & scientific | 2018 |
| Fortitude System Engineering Ltd | Professional & scientific | 2014 |
| Fortunella Limited | Hospitality | 2013 |
| Forté London Limited | Wholesale & retail | 2026 |
| Forward Watersports Limited | Education | 2023 |
| Fossick Digital Ltd | Information & communication | 2016 |
| Four Fish Ltd | Real estate | 2019 |
| Four Seasons Fuel Ltd | Wholesale & retail | 2002 |
| Fourfoursix Limited | Manufacturing | 2019 |
| Fourmation Design Consultants Limited | Professional & scientific | 2005 |
| Fozzie House Limited | Professional & scientific | 2017 |
| FPK LIS Ltd | Real estate | 2025 |
| FPL Family Limited | Arts & recreation | 2019 |
| Fractio Partners Ltd | Professional & scientific | 2026 |
| Frame & Velocity Limited | Professional & scientific | 2026 |
| France Hotel Services Limited | Administrative & support | 2017 |
| Francis Ross Ltd | Information & communication | 2007 |
| Frankie & Marley Limited | Wholesale & retail | 2024 |
| Fraser Kirkcaldy Architects Ltd | Professional & scientific | 1991 |
| Fraser Meirion Productions Ltd | Information & communication | 2026 |
| Fraser Watson Limited | Real estate | 1998 |
| Fraze Ltd | Administrative & support | 2017 |
| Free Air Health Ltd | Wholesale & retail | 2024 |
| Free Range Entertainment Limited | Information & communication | 2022 |
| Free Water Project CIC | Water & waste | 2025 |
| Freeform Trading Ltd. | Financial services | 2018 |
| Freeway Trade Limited | Other services | 2017 |