| Flexy Corporation Ltd | Administrative & support | 2015 |
| Flexyflow Ltd | Transport & logistics | 2019 |
| Flight 380 Ltd | Administrative & support | 2019 |
| Flight Pro International Ltd | Other services | 2020 |
| FLIGHTS4U Limited | Administrative & support | 2025 |
| Flint Court Limited | Households | 2001 |
| FLITES4U Limited | Administrative & support | 2025 |
| Flitwick Helicopters Limited | Administrative & support | 2014 |
| FLM Electrics Ltd | Construction | 2026 |
| FLO Heating & Plumbing Ltd | Construction | 2023 |
| Flobella Kitchens & Bathrooms Ltd | Construction | 2023 |
| Flobella Property Ltd | Real estate | 2025 |
| Flooring Pro Ltd | Wholesale & retail | 2016 |
| Flooring Services Luton Ltd | Wholesale & retail | 2021 |
| Flooring Solutions (Toddington) Limited | Construction | 2015 |
| Floorscreed Limited | Construction | 2002 |
| Floral & Co by Mariyah Ltd | Wholesale & retail | 2023 |
| Floredeluxe Ltd | Wholesale & retail | 2026 |
| Florence Property Group Ltd | Real estate | 2024 |
| Florence Street (Hitchin) Management Company Limited | Real estate | 2007 |
| Florete Flores Limited | Professional & scientific | 2021 |
| Floriana Cleaning Services Ltd | Administrative & support | 2024 |
| Florin Construct Services Ltd | Construction | 2021 |
| Florin&Alina Limited | Transport & logistics | 2024 |
| Florsense Ltd | Wholesale & retail | 2024 |
| Flow Plumbin Limited | Construction | 2022 |
| Flowers by George Ltd | Wholesale & retail | 2019 |
| Flowers Fostering Ltd | Administrative & support | 2018 |
| Flowersforu Ltd | Wholesale & retail | 2021 |
| Flowficient Ltd | Information & communication | 2026 |
| Flowmec Limited | Construction | 2017 |
| Floxi Services Ltd | Real estate | 2022 |
| Flucast Limited | Real estate | 1987 |
| Flux Flow Ltd | Construction | 2019 |
| Fluxdigital Ltd | Wholesale & retail | 2025 |
| FLY Marketing Group Limited | Professional & scientific | 2026 |
| FLY Speed Couriers Ltd | Transport & logistics | 2024 |
| Flycityuk Musicandvisual Group Ltd | Information & communication | 2019 |
| Flyhighuk Ltd | Transport & logistics | 2026 |
| Flying Colours Design Consultants Limited | Professional & scientific | 1997 |
| Flying Pizza (Beds) Ltd | Hospitality | 2024 |
| Flyingearth Ltd | Wholesale & retail | 2018 |
| Flymoon Limited | Transport & logistics | 2020 |
| Flynn Investments LLP | | 2014 |
| Flynn James Properties Limited | Construction | 2020 |
| Flytech Aviation Limited | Transport & logistics | 2011 |
| Flytippers R US Limited | Water & waste | 2023 |
| FM Motorist Ltd | Wholesale & retail | 2025 |
| FM Quality Care Ltd | Health & social care | 2026 |
| FM Smart Cleaning Ltd | Administrative & support | 2023 |
| FM Tyre Care Limited | Wholesale & retail | 2022 |
| FMD Global Ltd | Wholesale & retail | 2025 |
| FMG Works Limited | Administrative & support | 2026 |
| FMJ Global Ltd | Wholesale & retail | 2024 |
| FMV & Ace Logistics Ltd | Transport & logistics | 2023 |
| FN Automotive Ltd | Wholesale & retail | 2024 |
| FNL Media Solutions Ltd | Information & communication | 2016 |
| Focus Financials (UK) Limited | Professional & scientific | 2009 |
| Focus Private Care Ltd | Health & social care | 2019 |
| Focus Sound and Light Limited | Arts & recreation | 2015 |
| FOI Flooring Ltd | Construction | 2018 |
| Fola Fabrics Ltd | Manufacturing | 2020 |
| Foley Property Ltd | Real estate | 2024 |
| Fonesmart Luton Limited | Wholesale & retail | 2016 |
| Fontis Limited | Information & communication | 2001 |
| Fontis Projects Limited | Professional & scientific | 2014 |
| Fontis Property Group Ltd | Real estate | 2026 |
| Fontis Property LLP | | 2023 |
| Fontora Limited | Wholesale & retail | 2025 |
| Fonz & M Services Ltd | Transport & logistics | 2023 |
| Food Deliveries Limited | Other services | 2025 |
| Food Fellas Takeaway Ltd | Hospitality | 2023 |
| Food Haus Ltd | Hospitality | 2025 |
| Food Packaging Direct Ltd | Wholesale & retail | 2020 |
| Food Review Club Limited | Information & communication | 2019 |
| Food, Spices & General Trading Company Ltd | Hospitality | 2013 |
| Foodclub Peri Peri Ltd | Hospitality | 2025 |
| Foodie Cottage Ltd | Hospitality | 2019 |
| Foodie Halal Limited | Hospitality | 2025 |
| FOODIEFUSION2025 Ltd | Hospitality | 2025 |
| Foodlight Limited | Professional & scientific | 2010 |
| Foodozone Limited | Hospitality | 2026 |
| Foodpire Limited | Wholesale & retail | 2020 |
| Foodpire Luton Limited | Hospitality | 2022 |
| Foodvaille Ltd | Hospitality | 2019 |
| Foodwebs Ltd | Wholesale & retail | 2022 |
| Football Training and Development Ltd | Education | 2019 |
| Footcare First Ltd | Health & social care | 2020 |
| Foptics Limited | Health & social care | 2012 |
| FOR ALL of US CIC | Public administration | 2025 |
| FOR Your Entertainment Limited | Professional & scientific | 2019 |
| Ford Construction Services Limited | Construction | 2019 |
| Fordee Limited | Information & communication | 2026 |
| Forest Guardian Ltd | Agriculture & fishing | 2025 |
| Forest View (Sandridge) Management Limited | Real estate | 2017 |
| Forever Dunn Ltd | Real estate | 2026 |
| Forever Traders Ltd | Wholesale & retail | 2019 |
| Forever Yours Healthcare Ltd | Health & social care | 2022 |
| Forklift Hire Solutions Limited | Administrative & support | 2025 |
| Form I T Solutions Limited | Professional & scientific | 2008 |