| Flask Lane Ltd | Information & communication | 2012 |
| Flaskgate Limited | Construction | 1981 |
| Flat Earth Industries Limited | Information & communication | 2009 |
| Flat White Plastering Ltd | Construction | 2023 |
| Flatgoal Limited | Real estate | 2002 |
| Flattmai Abode Ltd | Real estate | 2021 |
| Flaunden Lane Property Management Limited | Real estate | 2019 |
| Flaunden Lane Property Services Limited | Real estate | 2017 |
| Flav's Flooring Ltd | Construction | 2019 |
| Flavour Foundry Ltd | Manufacturing | 2025 |
| Flavourrush Pizza Ltd | Hospitality | 2025 |
| Flavr Web DEV Ltd | Information & communication | 2023 |
| Flaways Ltd | Transport & logistics | 2017 |
| Flawless Exteriors Ltd | Construction | 2025 |
| Flawless Facilities Ltd | Administrative & support | 2024 |
| FLC Sports Ltd | Manufacturing | 2022 |
| Fleet Force Haulage Ltd | Transport & logistics | 2024 |
| Fleet Wraps Limited | Professional & scientific | 2025 |
| Fleetguard+ Ltd | Professional & scientific | 2026 |
| Fleming Medical Limited | Administrative & support | 2012 |
| Flettner Ventilator Limited | Manufacturing | 1931 |
| Flevera Limited | Information & communication | 2026 |
| Flex Infrastructure Projects Limited | Professional & scientific | 2022 |
| Flexi Care Solutions Ltd | Health & social care | 2020 |
| Flexibility Multimedia Ltd | Arts & recreation | 2025 |
| Fleximation Limited | Information & communication | 2020 |
| Flexlink Systems Limited | Manufacturing | 1984 |
| Flexur Systems UK Ltd | Information & communication | 2012 |
| Flickerbox Limited | Administrative & support | 2008 |
| Flight School X Chamber Gang Ltd | Arts & recreation | 2026 |
| Flights and Dreams Limited | Other services | 2003 |
| Flintframe Limited | Construction | 1997 |
| Flintshire Composites Limited | Manufacturing | 2022 |
| Floatdene Training Limited | Information & communication | 2018 |
| Floating Pocket Ltd | Wholesale & retail | 2024 |
| Flodge Farm Limited | Agriculture & fishing | 2018 |
| Flood Force Ltd | Construction | 2023 |
| Floodflow Marketing Ltd | Professional & scientific | 2025 |
| Floor IT Milton Keynes Limited | Construction | 2016 |
| Flooring Distribution Supplies Ltd | Wholesale & retail | 2023 |
| Flooring to Go UK Ltd | Wholesale & retail | 2024 |
| Floorscreed (UK) Limited | Construction | 2005 |
| Flor & Co. London Ltd | Manufacturing | 2021 |
| Flora Tutor Ltd | Education | 2020 |
| Floraguard Ltd | Other services | 2024 |
| Florence Media Productions Ltd | Arts & recreation | 2019 |
| Florentin Builders Ltd | Construction | 2023 |
| Florfam Auto Ltd | Wholesale & retail | 2023 |
| Florhenium Ltd | Other services | 2023 |
| Florismart Holdings Limited | Financial services | 2016 |
| Florismart UK Ltd | Information & communication | 2014 |
| Floryn Holdings Group Limited | Transport & logistics | 2018 |
| Flossit Ltd | Health & social care | 2009 |
| Flourish HR & Coaching Limited | Administrative & support | 2024 |
| Flower Energy Construction Ltd | Construction | 2016 |
| Flowerscale Ltd | Other services | 2024 |
| Flowforge Plumbing Ltd | Construction | 2026 |
| Flowiin Ltd | Information & communication | 2026 |
| Flowing River Holding Ltd | Hospitality | 2026 |
| Flowtech Plumbing & Heating Services Ltd | Construction | 2026 |
| Floxy Consulting Limited | Health & social care | 2014 |
| FLP Investments Limited | Financial services | 2012 |
| Fluff and Tumble (MK) Ltd | Other services | 2015 |
| Fluffenhund Limited | Other services | 2025 |
| Fluidic Analytics Limited | Professional & scientific | 2013 |
| Flukes Group Limited | Administrative & support | 2025 |
| Flush MK Ltd | Construction | 2023 |
| Flutter MK Ltd | Other services | 2018 |
| FLY Saudi Ltd | Professional & scientific | 2022 |
| Fly-High Properties Ltd | Real estate | 2019 |
| Flyby Food and Alcohol Ltd | Wholesale & retail | 2024 |
| Flying Fairies Day Care Nursery Ltd | Health & social care | 2022 |
| Flying Fibre Ltd | Construction | 2020 |
| Flying Hotdogs Limited | Extraterritorial | 2022 |
| Flying Hybrid Ltd | Arts & recreation | 2024 |
| Flying Panda MK Limited | Hospitality | 2025 |
| Flynn Lettings Limited | Real estate | 2006 |
| Flyseo Ltd | Information & communication | 2025 |
| FLZ Transport Ltd | Transport & logistics | 2025 |
| FM Electrical Engineering Services Ltd | Construction | 2019 |
| Fm&H Ltd | Health & social care | 2013 |
| Fmdja Limited | Administrative & support | 2014 |
| FMF Transport Logistics Limited | Transport & logistics | 2026 |
| FMI Systems Limited | Information & communication | 2024 |
| FMN Marketing Ltd | Wholesale & retail | 2011 |
| FMN Quality Care Limited | Health & social care | 2016 |
| FMS Property Holdings Limited | Financial services | 2025 |
| FND Ecommerce Limited | Wholesale & retail | 2021 |
| FNI Enterprise Ltd | Real estate | 2019 |
| FO Property Ltd | Real estate | 2025 |
| Foamlife Ltd | Manufacturing | 2020 |
| Focal Integration Solutions Ltd | Construction | 2018 |
| Focus 90+ Sports Coaching Ltd | Education | 2026 |
| Focus Response Limited | Professional & scientific | 2020 |
| Focused Solutions Group Limited | Administrative & support | 2024 |
| Fodni Ltd | Hospitality | 2025 |
| Fodok Property Investment Limited | Real estate | 2022 |
| Fodok Solutions UK Limited | Information & communication | 2007 |
| FOF Digital Limited | Other services | 2016 |
| FOF Events Limited | Administrative & support | 2009 |