| Firm-Foundation Counselling Centre Limited | Health & social care | 2006 |
| Firman Glass Limited | Extraterritorial | 2010 |
| First Annette Limited | Households | 2019 |
| First Best Limited | Real estate | 2023 |
| First Class Business Services Limited | Professional & scientific | 2017 |
| First Class Finishings Ltd | Construction | 2024 |
| First Class Fitness Academy Ltd. | Education | 2020 |
| First Credit Advice Limited | Administrative & support | 2012 |
| First Crown Recruitment Limited | Financial services | 2018 |
| First Doctors Limited | Health & social care | 2013 |
| First Force Security Services Ltd | Administrative & support | 2014 |
| First Homes Limited | Construction | 2013 |
| First Klass Limited | Construction | 2025 |
| First Line Academy Ltd | Information & communication | 2024 |
| First Line Care Limited | Health & social care | 2019 |
| First Line Group Limited | Financial services | 2022 |
| First Line Network Limited | Wholesale & retail | 2025 |
| First Marina Limited | Other services | 2021 |
| First Media Response Ltd | Real estate | 2012 |
| First Modular Site Services Ltd | Construction | 2023 |
| First Place Nationwide Training Ltd | Education | 2025 |
| First Place Training Ltd | Education | 2025 |
| First Quality Builders Ltd | Construction | 2019 |
| First Space Ltd | Real estate | 2022 |
| First Step Education Ltd | Administrative & support | 2024 |
| Firsttimerstech Ltd | Wholesale & retail | 2024 |
| FIS Tilling Ltd | Construction | 2016 |
| Fisher Crafted Interiors Ltd | Construction | 2025 |
| Fisher Entertainment Ltd | Information & communication | 2018 |
| Fit Fuel Beauty Ltd | Wholesale & retail | 2026 |
| FIT4LIFE Group Ltd | Arts & recreation | 2019 |
| Fitness by APT Ltd | Arts & recreation | 2014 |
| Fitness HQ Gyms Ltd | Health & social care | 2022 |
| Fitya Centre | Education | 2024 |
| Five Boys GAS Ltd | Professional & scientific | 2021 |
| Five Bros & Co Limited | Hospitality | 2018 |
| Five Knights Investment Limited | Real estate | 2013 |
| Five Oaks Access Ltd | Construction | 2019 |
| Five Points London Ltd | Health & social care | 2016 |
| Five Star Property Management Limited | Real estate | 1984 |
| Five Star Staffing Solutions Ltd | Administrative & support | 2025 |
| Five Star Support Services Limited | Administrative & support | 2021 |
| FIVE1987 Ltd | Construction | 2024 |
| Fivestar Plumbingand Heating Services Ltd | Construction | 2022 |
| Fixtal Ltd | Construction | 2023 |
| Fizaz Ltd | Wholesale & retail | 2026 |
| Fizmani Groundworks Ltd | Construction | 2023 |
| Fizzbiz Ltd | Wholesale & retail | 2025 |
| FJ (LDN) Limited | Other services | 2023 |
| FJ Housing Limited | Real estate | 2025 |
| FJA Drylining Ltd | Financial services | 2019 |
| FJG Interiors Ltd | Construction | 2020 |
| Fjim Ltd | Real estate | 2025 |
| FK Fort Limited | Construction | 2012 |
| FKN Consultancy Ltd | Professional & scientific | 2019 |
| FKO Healthcare Ltd | Wholesale & retail | 2025 |
| Fkwc Ltd | Education | 2024 |
| FL Building Services Ltd | Construction | 2019 |
| Flack Consultancy Limited | Financial services | 2021 |
| Flama Limited | Hospitality | 2024 |
| Flame Ideas Ltd | Construction | 2018 |
| Flame Learning & Development Ltd | Education | 2012 |
| Flamesfightgear Ltd | Wholesale & retail | 2025 |
| Flamo Candles Limited | Wholesale & retail | 2022 |
| Flarxs Limited | Information & communication | 2024 |
| Flashforward London Limited | Professional & scientific | 2010 |
| Flat Face Animation Ltd | Information & communication | 2019 |
| Flavor Wings Limited | Hospitality | 2024 |
| Flavours of Jamrock Ltd | Hospitality | 2024 |
| Flawless Future Limited | Information & communication | 2023 |
| Flawless Landscaping Ltd | Administrative & support | 2023 |
| Fleet Repair & Maintenance Ltd | Wholesale & retail | 2023 |
| Fleetsavvy Management Ltd | Other services | 2024 |
| Flemings Contractors Limited | Construction | 2017 |
| Flexeho Ltd | Professional & scientific | 2025 |
| Flexfog Ltd | Wholesale & retail | 2014 |
| Flexi Car Rentals Ltd | Administrative & support | 2023 |
| Flexibility Research Ltd | Education | 2019 |
| Flexible Polymerics Ltd | Manufacturing | 2022 |
| Flexshield Ventures Limited | Professional & scientific | 2020 |
| Flexx BE Flexitarian Limited | Other services | 2019 |
| Flexxy Education Limited | Education | 2024 |
| Fliee UK Limited | Wholesale & retail | 2023 |
| Flight Aviation Travel Limited | Administrative & support | 2025 |
| Flights World Ltd | Administrative & support | 2024 |
| Flink Service Ltd | Construction | 2022 |
| Flintrr Limited | Information & communication | 2019 |
| Flippin Sweet Ltd | Hospitality | 2025 |
| Flipside Consulting Limited | Professional & scientific | 2026 |
| FLO Solutions Limited | Construction | 2011 |
| Flo&P Ltd | Construction | 2017 |
| Flobengo Limited | Health & social care | 2020 |
| FLOORCARE4LESS Ltd | Administrative & support | 2022 |
| Flopop Ltd | Transport & logistics | 2014 |
| Flora Property Investments Ltd | Real estate | 2024 |
| Florabelle Luxury Flowers Ltd. | Wholesale & retail | 2017 |
| Florence Care Services Limited | Health & social care | 2020 |
| Florent Property Limited | Households | 2025 |
| Florida Fast Food Ltd | Hospitality | 2025 |
| Floryn Transport Ltd | Transport & logistics | 2017 |