| First Impression DRY Cleaners Ltd | Other services | 2014 |
| First LET Management Limited | Real estate | 2014 |
| First Light Property Co Ltd | Real estate | 2025 |
| First Line Fasteners Limited | Wholesale & retail | 2016 |
| First Line FM Ltd | Administrative & support | 2021 |
| First National Direct Limited | Extraterritorial | 2015 |
| First PAY Solutions Limited | Administrative & support | 2017 |
| First Quality Residentials Limited | Real estate | 2025 |
| First Rehabilitation and Physiotherapy Centre Limited | Health & social care | 2007 |
| First Spartan Security Services Ltd | Administrative & support | 2020 |
| First Step Property Services Ltd | Real estate | 2005 |
| First Steps Group Ltd | Education | 2017 |
| First Steps Learning Hub Ltd | Education | 2026 |
| First Study Ltd | Education | 2018 |
| First Style Limited | Construction | 2021 |
| First Tech Auto Limited | Other services | 2026 |
| First Vivid Ltd | Wholesale & retail | 2023 |
| Firstassistanceuk Limited | Transport & logistics | 2022 |
| Firstbase (Future Marketing) Limited | Financial services | 2012 |
| Firstbase IT Limited | Professional & scientific | 2000 |
| Firstchoicegoods Ltd | Wholesale & retail | 2025 |
| Firstcontact Pharmacy Ltd. | Health & social care | 2023 |
| Firsthope Limited | Real estate | 2008 |
| Firstilan Ltd | Real estate | 2025 |
| Firstline Contractors (London) Ltd | Transport & logistics | 2022 |
| Fiscal Wise Solutions Limited | Professional & scientific | 2017 |
| Fish & Chips Uxbridge Limited | Hospitality | 2022 |
| Fish and Meat Bazar Limited | Wholesale & retail | 2020 |
| Fisher Traders Limited | Wholesale & retail | 2025 |
| Fishersbay Limited | Real estate | 2022 |
| Fit 2 U Limited | Arts & recreation | 2025 |
| Fit Mama Ltd | Health & social care | 2023 |
| Fit Masters Shopfront Shutters Ltd | Construction | 2026 |
| Fit Trip Vending Limited | Manufacturing | 2024 |
| Fit With Kritika Ltd | Health & social care | 2025 |
| Fitbelle Health Ltd | Health & social care | 2022 |
| Fitgopro Ltd | Other services | 2025 |
| Fitiz Ltd | Wholesale & retail | 2022 |
| Fitness Within Limited | Manufacturing | 2019 |
| Fitrage Ltd | Wholesale & retail | 2024 |
| Five a Medical Ltd | Health & social care | 2023 |
| Five Chai Ltd | Hospitality | 2025 |
| Five Falavours Limited | Wholesale & retail | 2023 |
| Five Fellas UK Limited | Wholesale & retail | 2024 |
| Five Pencils Limited | Wholesale & retail | 2012 |
| Five Pillars Capital Ltd | Other services | 2018 |
| Five Pillars Decorating Ltd | Construction | 2025 |
| Five Pillars Property Management Ltd | Construction | 2022 |
| Five Rivers 13 Ltd | Real estate | 2025 |
| Five Sense Resources Ltd | Wholesale & retail | 2025 |
| Five Shades Productions Ltd | Wholesale & retail | 2024 |
| Five Shadows Limited | Real estate | 2021 |
| Five SIX Three Worldwide Ltd | Other services | 2014 |
| Five Star Design and Build Ltd | Real estate | 2005 |
| Five Star Fisheries Ltd | Wholesale & retail | 2011 |
| Five Star Motor Cars Ltd | Wholesale & retail | 2022 |
| Five Star Private Limited | Wholesale & retail | 2017 |
| Five Stars Builders Ltd | Construction | 2025 |
| Five Stars Care Services Ltd. | Health & social care | 2016 |
| FIX & Chill Ltd | Wholesale & retail | 2026 |
| FIX Gadget Online Ltd | Administrative & support | 2017 |
| Fix-Prop Ltd | Construction | 2025 |
| Fixensy Limited | Information & communication | 2022 |
| Fixit Heating & Plumbing Supplies Ltd | Construction | 2016 |
| Fixnow Limited | Real estate | 2018 |
| Fixpedia Limited | Construction | 2019 |
| Fixy Ltd | Construction | 2019 |
| Fiyaah Limited | Wholesale & retail | 2025 |
| Fiybit Group Limited | Financial services | 2023 |
| FIZ One Ltd | Real estate | 2025 |
| Fiza Cosmetics Limited | Wholesale & retail | 2021 |
| Fiza Investment Ltd | Financial services | 2022 |
| Fizas Consultancy Limited | Professional & scientific | 2018 |
| FJ Buta Plumbing & Heating Ltd | Administrative & support | 2017 |
| FJ Medical Ltd | Health & social care | 2021 |
| FJ Trading Limited | Wholesale & retail | 2025 |
| Fj&N Properties Limited | Real estate | 2022 |
| FK Accountants Limited | Professional & scientific | 2013 |
| FK Electrical and Plumbing Supplies Limited | Wholesale & retail | 2020 |
| FK Global Services Ltd | Professional & scientific | 2024 |
| FK Medical Consulting Limited | Health & social care | 2023 |
| FK Wash Ltd | Other services | 2012 |
| FKS Properties Limited | Real estate | 2021 |
| Flairwise Ltd | Health & social care | 2025 |
| Flame Property Services Ltd | Real estate | 2023 |
| Flame Restaurant and Banqueting Ltd | Hospitality | 2022 |
| Flame Venue Hire Ltd | Hospitality | 2023 |
| Flamenex Ltd | Professional & scientific | 2024 |
| Flanelol Ltd | Health & social care | 2019 |
| Flare Care Limited | Real estate | 2026 |
| Flare Technology Limited | Professional & scientific | 2021 |
| Flash FX Ltd | Administrative & support | 2024 |
| Flash Recovery Ltd | Transport & logistics | 2025 |
| Flash Waste Removal Ltd | Water & waste | 2024 |
| Flat Iron (UK) Limited | Administrative & support | 2008 |
| Flava DAT Ltd | Hospitality | 2025 |
| Flavers Food Ltd | Hospitality | 2026 |
| Flavorino Pizza Ilford Ltd | Hospitality | 2025 |
| Flavours & Spices Ltd | Wholesale & retail | 2012 |
| Flavours of Punjab Limited | Hospitality | 2019 |