| Florentina C Ltd | Transport & logistics | 2026 |
| Floreo Consulting Limited | Professional & scientific | 2010 |
| Flourish Online Consulting Limited | Professional & scientific | 2019 |
| Flourish Support Limited | Health & social care | 2021 |
| Flowers on the Wall Ltd | Hospitality | 2024 |
| Fluent Languages UK Limited | Other services | 2020 |
| Fluent Momentum Limited | Education | 2021 |
| Fluid Research Ltd | Manufacturing | 1971 |
| Flying Horse Properties Ltd | Real estate | 2020 |
| FMB Telecom Ltd | Information & communication | 2025 |
| Focal Medical Ltd | Administrative & support | 2023 |
| Food for Thought Northants Ltd | Wholesale & retail | 2022 |
| Food Plus JK Ltd | Wholesale & retail | 2024 |
| FOR 7 Days Ltd | Wholesale & retail | 2026 |
| Forbells Ltd | Hospitality | 2017 |
| Forbes Business Solutions Ltd | Professional & scientific | 2009 |
| Fordham Stand Solutions Limited | Administrative & support | 2011 |
| Foreign Affairs Towcester Limited | Wholesale & retail | 2023 |
| Foresight & Nova Ltd | Professional & scientific | 2011 |
| Foreza Limited | Transport & logistics | 2016 |
| Forgehomes Limited | Construction | 2018 |
| Formation Marketing Ltd | Professional & scientific | 2017 |
| Formation Partners Limited | Information & communication | 2023 |
| Formula Plumb Ltd | Construction | 2025 |
| Formwise Washrooms Ltd | Manufacturing | 2008 |
| Forstarr Building Services Limited | Construction | 1997 |
| Forwardzone Property Management Limited | Other services | 1990 |
| Fountain of Hope Sanctuary | Education | 2018 |
| Fountains Therapy Centre Limited | Other services | 2019 |
| Four Seven FM Ltd | Administrative & support | 2025 |
| FOX Hollow Developments Ltd | Real estate | 2025 |
| FPE Holdings Limited | Financial services | 2016 |
| FR Home to Home Ltd | Health & social care | 2024 |
| Fraddon Biogas Limited | Energy | 2013 |
| Frama Care Services Limited | Public administration | 2019 |
| Francis Roofing Limited | Construction | 2018 |
| Francis UK Properties Ltd | Real estate | 2019 |
| Frank Cook Motors Limited | Wholesale & retail | 2014 |
| Frankie Treecare and Garden Services Limited | Administrative & support | 2015 |
| Frankies Homes Ltd | Real estate | 2025 |
| Freedom Motorcycle Engineering Limited | Wholesale & retail | 2021 |
| Freemarch Bricklaying Limited | Construction | 2017 |
| Freestyle Curriculum Solutions Ltd | Arts & recreation | 2010 |
| Freestyle Dodgeball UK Ltd | Arts & recreation | 2013 |
| Freestyle Holiday Camps Ltd | Arts & recreation | 2014 |
| Freestyle Team Fundamentals Ltd | Arts & recreation | 2010 |
| Freestyle U-Dance Ltd | Arts & recreation | 2011 |
| Freetrack Group Ltd | Professional & scientific | 2025 |
| Freight Distribution Ltd | Transport & logistics | 2022 |
| Fresh Clean Binz Ltd | Administrative & support | 2025 |
| Fresh Clean Drives Ltd | Administrative & support | 2025 |
| Fresh Ideas Direct Limited | Wholesale & retail | 2007 |
| Fresh Italian Food Ltd | Wholesale & retail | 2025 |
| Fresh Stream Growers Ltd | Administrative & support | 2017 |
| Fresh Stream Services Limited | Wholesale & retail | 2016 |
| Freshcleanbins Ltd | Administrative & support | 2021 |
| Freya Transport Ltd | Transport & logistics | 2025 |
| Freybell Property Investments Ltd | Real estate | 2024 |
| Friendly Ease Solution Ltd | Extraterritorial | 2024 |
| Friends Advisers Cambs Ltd | Financial services | 2017 |
| Frisby and SON Limited | Wholesale & retail | 2014 |
| Frisby Automotive Ltd | Wholesale & retail | 2020 |
| Frontline I.T. Ltd | Professional & scientific | 1996 |
| Frontline Trading Limited | Wholesale & retail | 2005 |
| Frosty Fields Estate Agents Ltd | Real estate | 2020 |
| FRU Trans Limited | Transport & logistics | 2025 |
| Frugro Ltd | Wholesale & retail | 2016 |
| Fruits and Roots Ltd | Wholesale & retail | 2018 |
| Fsed Limited | Professional & scientific | 2015 |
| Fseg Limited | Professional & scientific | 2002 |
| Fstoxconsulting Ltd | Professional & scientific | 2017 |
| Fuat's Art School Ltd | Administrative & support | 2019 |
| Fufu Ltd | Transport & logistics | 2013 |
| Fujela Links Limited | Health & social care | 2016 |
| Fulcrum Services Limited | Information & communication | 2020 |
| Full Constructor Ltd | Transport & logistics | 2021 |
| Full Monty Plastering Ltd | Construction | 2017 |
| Fuller Sourced and QC Limited | Wholesale & retail | 2023 |
| Fullpen Fabrications Limited | Manufacturing | 2023 |
| FUR Coat NO Knickers Theatre Limited | Arts & recreation | 2022 |
| Furnital Limited | Real estate | 1985 |
| Fusion Tech Group Ltd | Financial services | 2025 |
| Fusion Tech Limited | Administrative & support | 2007 |
| Fusion Tech Property Ltd | Administrative & support | 2025 |
| Future Foundations Living Ltd | Health & social care | 2024 |
| Future Lions Europe Ltd | Arts & recreation | 2015 |
| Futurekleen Ltd | Construction | 2009 |
| Futurescapes Limited | Construction | 2022 |
| FX Couriers Ltd | Transport & logistics | 2025 |
| Fxplace Ltd | Real estate | 2025 |
| Fxrob Ltd | Transport & logistics | 2019 |
| G & N Engineering Ltd | Professional & scientific | 2020 |
| G Breslin Construction Limited | Construction | 2023 |
| G Heasman & Co Ltd | Manufacturing | 2023 |
| G Johnston Limited | Construction | 2022 |
| G L Mills Property Company Limited | Real estate | 2023 |
| G L Nicholls Brickwork Limited | Administrative & support | 2014 |
| G Lawless Limited | Construction | 2010 |
| G R Employment Limited | Administrative & support | 2013 |
| G&F Plumbing and Heating Ltd | Construction | 2026 |