| Flex Pass Ltd | Administrative & support | 2024 |
| Flexi Tots Ltd | Manufacturing | 2025 |
| Flexible Hydraulic Solutions Limited | Wholesale & retail | 2014 |
| Flexiedu Ltd | Information & communication | 2025 |
| Flexify Ltd | Wholesale & retail | 2025 |
| Flickerboxx Ltd | Information & communication | 2018 |
| Flight CK Ltd | Other services | 2025 |
| FLIGHT9 Ltd | Education | 2025 |
| Flipbrgr Ltd | Hospitality | 2024 |
| Flipkin Trading Limited | Wholesale & retail | 2021 |
| Flipzaa Ltd | Wholesale & retail | 2025 |
| Fliteline Autosales Limited | Wholesale & retail | 2011 |
| Floral and Craft Warehouse Limited | Wholesale & retail | 2014 |
| Flortoria Ltd | Wholesale & retail | 2022 |
| Flotech Recruit Ltd | Information & communication | 2026 |
| Flourish HER Ltd | Wholesale & retail | 2025 |
| FLOURISH2THRIVE Limited | Health & social care | 2024 |
| Flow Surge Ltd | Wholesale & retail | 2024 |
| Flow&Ebb Edge Limited | Professional & scientific | 2025 |
| Flow&Ebb Limited | Professional & scientific | 2015 |
| Flow&Ebb Renewables Limited | Professional & scientific | 2022 |
| Flowca Ltd | Professional & scientific | 2026 |
| Flowcess Ltd | Professional & scientific | 2026 |
| Flowly Ltd | Professional & scientific | 2023 |
| Flowmint Ltd | Information & communication | 2025 |
| Flowzain Ltd | Information & communication | 2025 |
| Floyd & Linx Limited | Other services | 2022 |
| Floyd Design & Build Ltd | Construction | 2023 |
| FLP Motors Ltd | Manufacturing | 2016 |
| FLR Property Limited | Real estate | 2024 |
| FLT Services Limited | Administrative & support | 2024 |
| Fluent Path Ltd | Education | 2024 |
| Fluezy's Ltd | Administrative & support | 2025 |
| Fluffykins & Saurus Ltd | Information & communication | 2026 |
| Fluid Mind Ltd | Education | 2020 |
| Fluora Ltd | Information & communication | 2026 |
| Fluorocarbon Pensions Limited | Professional & scientific | 2017 |
| Fluxa Ltd | Information & communication | 2026 |
| Fluxt Ltd | Professional & scientific | 2026 |
| Flycarb Ltd | Manufacturing | 2024 |
| Flying Rectangle Limited | Information & communication | 2021 |
| Flying Visits Ltd | Real estate | 2025 |
| Flyingsponge Ltd | Administrative & support | 2026 |
| Flywheel Magazine Ltd | Information & communication | 2025 |
| Flywithpigeon Ltd | Information & communication | 2026 |
| FM Client Accounting Ltd | Professional & scientific | 2024 |
| FM Collective Ltd | Real estate | 2026 |
| FM Global Links Ltd | Information & communication | 2015 |
| FMT Assets Ltd | Professional & scientific | 2021 |
| Fnscreator Ltd | Wholesale & retail | 2025 |
| Foad Exports Ltd | Wholesale & retail | 2025 |
| Foam-Away Extraction Specialists Limited | Construction | 2024 |
| Foci Business Consulting Limited | Professional & scientific | 2025 |
| Focus Plumbing & Heating Services Limited | Construction | 2022 |
| Focused Minds Creative Ltd | Information & communication | 2023 |
| Focuswaves Marketing Ltd | Professional & scientific | 2025 |
| Fodde Properties Limited | Real estate | 2023 |
| Foehammer Studios Ltd | Information & communication | 2026 |
| Foffum Developments Limited | Real estate | 1973 |
| Fogs & Prospect Ltd | Households | 2025 |
| Folk Suffolk Ltd | Agriculture & fishing | 2022 |
| Folklike Limited | Professional & scientific | 2022 |
| Follow the Shine Facilities Management Limited | Administrative & support | 2023 |
| Follow the Shine Ltd | Administrative & support | 2020 |
| Followedit Limited | Information & communication | 2020 |
| Folly Farm (Mildenhall) Limited | Agriculture & fishing | 1967 |
| Fontana HGH Ltd | Wholesale & retail | 2023 |
| Fontsey Holdings Limited | Financial services | 2020 |
| Food & Drink Consultancy Ltd | Wholesale & retail | 2010 |
| Food for Thought Consultancy Services Limited | Hospitality | 2016 |
| Food Processing Solutions UK Limited | Wholesale & retail | 2008 |
| Foodamour Ltd | Hospitality | 1990 |
| Foodfax Limited | Professional & scientific | 1983 |
| Foodtease Ltd | Information & communication | 2023 |
| Footprint Healthcare Solutions Ltd | Administrative & support | 2026 |
| Footy Fits Ltd | Wholesale & retail | 2023 |
| Fora Food Service Ltd | Wholesale & retail | 2016 |
| Forage & Season Group Limited | Hospitality | 2024 |
| Forbes Lettings Ltd | Real estate | 2025 |
| Force Brewery Limited | Agriculture & fishing | 2012 |
| Forde Retail Limited | Wholesale & retail | 2020 |
| Forenew Limited | Wholesale & retail | 2025 |
| Forest Heath Public Radio Limited | Information & communication | 2008 |
| Forest School Association | Education | 2012 |
| Forest Shadows Ltd. | Wholesale & retail | 2021 |
| Forest View Services Ltd | Agriculture & fishing | 2025 |
| Forestspace Limited | Information & communication | 2023 |
| Forever Global Group Limited | Financial services | 2018 |
| Forfarmers UK Holdings Limited | Manufacturing | 2012 |
| Forfarmers UK Limited | Manufacturing | 1899 |
| Forge Consultancy Limited | Professional & scientific | 2003 |
| Forge Court (Ardleigh) Limited | Households | 2006 |
| Forge PM Ltd | Construction | 2025 |
| Forgetandfly Limited | Administrative & support | 2025 |
| Forgoodsponsors Ltd | Information & communication | 2025 |
| Foriety Ltd | Information & communication | 2019 |
| Fork and Fire Food Ltd | Wholesale & retail | 2022 |
| FORKLIFTS4LESS Ltd | Administrative & support | 2024 |
| Forks and Fingers Limited | Hospitality | 2015 |
| Forks Collective CIC | Arts & recreation | 2025 |