| First Environment Technologies Limited | Financial services | 2022 |
| First National Limited | Administrative & support | 1990 |
| First Report (Holdings) Limited | Administrative & support | 2004 |
| First Report Limited | Administrative & support | 1989 |
| FIRST4 Cargo Handling Ltd | | 2009 |
| Firstfield Electrical Limited | Construction | 2007 |
| Firstfield Engineering Limited | Wholesale & retail | 2009 |
| Firstfield Plant Limited | Construction | 2017 |
| Firstfield Property Limited | Construction | 2015 |
| Firstlove Consult Limited | Financial services | 2021 |
| Firstsite Traffic Management Agency Limited | Construction | 2023 |
| FIS Group Suffolk Ltd | Professional & scientific | 2025 |
| FIS Property Ltd | Real estate | 2006 |
| FIS Windows and Conservatories Limited | Construction | 2009 |
| FIS Windows Ltd | Construction | 2006 |
| Fish Croft Ltd | Hospitality | 2020 |
| Fish Trade Supplies Limited | Wholesale & retail | 2006 |
| Fishion Limited | Professional & scientific | 2014 |
| Fishmo Ltd | Professional & scientific | 2023 |
| Fisho Limited | Hospitality | 2019 |
| Fit Marketing Limited | Wholesale & retail | 2007 |
| FIT39 UK Limited | Wholesale & retail | 2012 |
| Fitcore Europe Ltd | Arts & recreation | 2015 |
| Fitness Formula Limited | Arts & recreation | 2021 |
| Fitology Studio Ltd | Other services | 2021 |
| Five SIX Blue Limited | Wholesale & retail | 2014 |
| Five Star Auto Salvage Ltd | Wholesale & retail | 2015 |
| Five Star Printing Limited | Manufacturing | 1979 |
| Five Stars Painting Ltd | Construction | 2022 |
| Five STR Stays Ltd | Hospitality | 2024 |
| FIX Cleaning Liliana Limited | Administrative & support | 2025 |
| Fixed Income Solutions Limited | Administrative & support | 2006 |
| Fizz Consultancy Ltd | Wholesale & retail | 2016 |
| Fizz Properties Limited | Construction | 2009 |
| Fizzwig Designs Ltd | Information & communication | 2017 |
| FJK Healthcare Limited | Health & social care | 2012 |
| FKC (Anglia) Limited | Construction | 2012 |
| FKE Investments (East Anglia) Limited | Real estate | 2024 |
| Flag Hill Cars Ltd. | Wholesale & retail | 1994 |
| Flag Social Ltd | Wholesale & retail | 2024 |
| Flagship Property & Marine Ltd | Construction | 2011 |
| Flagstick Homes Ltd | Households | 2025 |
| Flair Flight Limited | Professional & scientific | 2016 |
| Flame Lily Foods Ltd | Manufacturing | 2024 |
| Flamestone Ltd | Construction | 2014 |
| Flash Town Records Limited | Information & communication | 2018 |
| Flat 5 Baltic Court Ltd | Real estate | 2022 |
| Flat Basset Services Limited | Manufacturing | 2025 |
| Flavia FLS Trans Limited | Transport & logistics | 2019 |
| Flavir Limited | Health & social care | 2024 |
| Flax Cultivation Limited | Agriculture & fishing | 2021 |
| Fleet Anchor Solutions Ltd | Transport & logistics | 2025 |
| Fleet Radar Ltd | Information & communication | 2026 |
| Fleeta Limited | Wholesale & retail | 2025 |
| Fleetwith Limited | Professional & scientific | 2006 |
| Fleming Properties (Eastern) Limited | Real estate | 2017 |
| Fletch Consultancy Services Limited | Professional & scientific | 2012 |
| Fletcher Road 1963 Limited | Extraterritorial | 2014 |
| Fletchers Services Ltd | Construction | 2026 |
| Flett Professional Services Limited | Health & social care | 2023 |
| Flex Invest Ltd | Construction | 2022 |
| Flexi Mart Global Ltd | Wholesale & retail | 2026 |
| Flexi PA Limited | Administrative & support | 2006 |
| Fleximize Capital Limited | Financial services | 2015 |
| Fleximize Limited | Financial services | 2010 |
| Fleximize Property Ltd | Real estate | 2016 |
| Fleximize Services Limited | Administrative & support | 2014 |
| Fleximize Technology Services Limited | Extraterritorial | 2016 |
| Flexoshop Limited | Manufacturing | 2011 |
| Fliite Limited | Information & communication | 2017 |
| Flint Hall Glamping and Events Ltd | Hospitality | 2024 |
| Flira Limited | Information & communication | 2024 |
| FLO & Co Studio Ltd | Professional & scientific | 2025 |
| Flock Suffolk Limited | Hospitality | 2022 |
| Flogas UK Pension Scheme Trustee Limited | Financial services | 2024 |
| Floodwise Group Limited | Transport & logistics | 2023 |
| Flossie and JEY TOO Ltd | Construction | 2023 |
| Flourish and Bean Limited | Hospitality | 2022 |
| Flow Ecommerce Ltd | Wholesale & retail | 2025 |
| Flow Global Solutions Ltd | Information & communication | 2026 |
| Flow Studio Ipswich Limited | Arts & recreation | 2012 |
| Flower and Garden (UK) Limited | Wholesale & retail | 2018 |
| Flower Rush Limited | Wholesale & retail | 2019 |
| Flowrate Plumbing & Heating Ltd | Construction | 2011 |
| Floyd-Daniel Healthcare Services Ltd | Health & social care | 2019 |
| Fluent INK Ltd | Education | 2026 |
| Fluffbusters Ltd | Administrative & support | 2018 |
| Fluid Ambition Ltd | Education | 2023 |
| Flux Attuned Limited | Professional & scientific | 2025 |
| Flux Contracting Limited | Agriculture & fishing | 2021 |
| Flybridge Services Limited | Administrative & support | 2019 |
| Flyinfo Limited | Manufacturing | 2025 |
| Flying Eagle 2021 Ltd | Transport & logistics | 2021 |
| Flying Kite Studios UK Ltd | Financial services | 2013 |
| Flypass Holidays Limited | Administrative & support | 2025 |
| Flytoez Dance Company Limited | Education | 2024 |
| FM Insights Ltd | Information & communication | 2025 |
| Fmcg Ltd | Wholesale & retail | 2024 |
| Fmds Services Ltd | Transport & logistics | 2018 |
| FNG Enterprise Ltd | Wholesale & retail | 2020 |