| First Pick Solutions Ltd | Professional & scientific | 2025 |
| First Premium Consult Ltd | Professional & scientific | 2019 |
| First Principles Studio Ltd | Information & communication | 2026 |
| First Properties (Midlands) Limited | Administrative & support | 1997 |
| First Property Management Ltd | Real estate | 2015 |
| First Provincial Properties Limited | Real estate | 1989 |
| First Provincial Securities Limited | Real estate | 1990 |
| First Response (Nottingham) Ltd | Transport & logistics | 2024 |
| First Response Finance Limited | Financial services | 1998 |
| First Response Property Developments Limited | Construction | 2023 |
| First Round TV Ltd | Information & communication | 2024 |
| First Scottish Searching Services Limited | Administrative & support | 1971 |
| First Serve Education Limited | Education | 2017 |
| First Stone Properties Ltd | Real estate | 2025 |
| First Sunrise Properties Ltd. | Real estate | 2020 |
| First Systems Limited | Other services | 2023 |
| First Testing Limited | Construction | 2002 |
| First Universal Enterprises Limited | Construction | 2008 |
| Firstcall 247 Limited | Administrative & support | 2018 |
| Firstcall 247 Properties Limited | Real estate | 2021 |
| Firstcall Global Service Limited | Wholesale & retail | 2026 |
| Firstcall Home Care Limited | Health & social care | 2023 |
| Firstclose Ltd | Professional & scientific | 2026 |
| Firstfix Recruitment Ltd | Administrative & support | 2011 |
| Firth & Scott (Insurance Brokers) Limited | Financial services | 1964 |
| Firthway Limited | Financial services | 2004 |
| FIS Consulting Ltd | Professional & scientific | 2016 |
| Fisch Design Group Limited | Financial services | 2026 |
| Fisch Design Limited | Administrative & support | 2003 |
| Fish Family Real Estate Ltd | Real estate | 2025 |
| Fish Nottingham Limited | Real estate | 2017 |
| Fish Real Estate LLP | | 2024 |
| Fisher Whatmoor Ltd | Education | 2012 |
| Fishermania Limited | Wholesale & retail | 2010 |
| Fishermen of Mens Ltd | Health & social care | 2025 |
| Fishers (Harrogate) Limited | Transport & logistics | 1988 |
| Fishforge Games Ltd | Wholesale & retail | 2025 |
| Fishpig Limited | Information & communication | 2011 |
| Fishpond Drive Management Company Limited | Households | 1994 |
| Fishpool Developments Limited | Construction | 2021 |
| Fit and Go Auto Centre Ltd | Other services | 2017 |
| Fit Fashion Tailoring Ltd | Other services | 2025 |
| Fit OPS Ltd | Wholesale & retail | 2025 |
| Fit-Out Interior Transformation Limited | Construction | 2022 |
| FIT2GO Physio Limited | Administrative & support | 2017 |
| FIT2GO Physio Screening Limited | Health & social care | 2018 |
| Fitasfk Ltd | Wholesale & retail | 2024 |
| Fitness 4 Women Ltd | Other services | 2024 |
| Fitness Market Place Limited | Wholesale & retail | 2008 |
| Fitness Republic Limited | Health & social care | 2019 |
| Fitness Solutions & Rehabilitation Limited | Arts & recreation | 2011 |
| Fitness With Favour CIC | Other services | 2026 |
| Fitray Limited | Health & social care | 1989 |
| Fittings 4 Shops Ltd | Wholesale & retail | 2014 |
| Fitz Associates Limited | Administrative & support | 2010 |
| Fitzmark Ltd | Manufacturing | 2004 |
| Fitzmark Promotions Ltd | Wholesale & retail | 2004 |
| Fitzrovia Films Limited | Information & communication | 2020 |
| Fitzroy Business Consultants Limited | Professional & scientific | 2016 |
| Fitzwilliam Wakefield Management Limited | Households | 2014 |
| Five Counties Garden Rooms Ltd | Administrative & support | 2022 |
| Five Global Limited | Administrative & support | 2017 |
| Five Nations Roller Derby CIC | Arts & recreation | 2021 |
| Five Rivers Capital Ltd | Financial services | 2025 |
| Five Star Nails 225 Ltd | Other services | 2025 |
| Five Star Sports Coaching Ltd | Education | 2021 |
| Five Star Turkish Barbers (LE) Ltd | Other services | 2025 |
| Five Transport Company Limited(The) | Professional & scientific | 1960 |
| Five Zeros Consultancy Limited | Health & social care | 2012 |
| FIVE57 Ltd | Wholesale & retail | 2017 |
| FIX a Drip Healthcare Limited | Health & social care | 2023 |
| FIX Capital Investments Ltd | Financial services | 2020 |
| FIX IT ALL Building Supplies Limited | Wholesale & retail | 2007 |
| FIX IT and Finish Ltd | Construction | 2025 |
| FIX IT DAN Limited | Construction | 2020 |
| FIX My Car Limited | Wholesale & retail | 2010 |
| FIX Sports Stats Limited | Professional & scientific | 2014 |
| Fixaglaze Ltd | Other services | 2017 |
| Fixarc Ltd | Manufacturing | 2012 |
| Fixing and Fittings Direct Ltd | Wholesale & retail | 2018 |
| Fixpulse Ltd | Construction | 2024 |
| FJ Bryan Consulting Ltd | Professional & scientific | 2026 |
| FJ MAC Limited | Real estate | 2019 |
| FJB Heating Limited | Construction | 2018 |
| Fjori Limited | Professional & scientific | 2011 |
| FJP Motors Ltd | Wholesale & retail | 2016 |
| FK Corporation Ltd | Wholesale & retail | 2025 |
| FK1 Properties Limited | Real estate | 2023 |
| FKB Psychology Consultancy Limited | Health & social care | 2024 |
| Fkrh Technologies Ltd | Information & communication | 2025 |
| FL Electrical and Automation Services Ltd | Construction | 2013 |
| FL Executive Search Ltd | Administrative & support | 2023 |
| Flagship Management Limited | Professional & scientific | 2006 |
| Flair Advertisement Ltd | Professional & scientific | 2024 |
| Flair Leisure Ltd | Professional & scientific | 2025 |
| Flair Picks Ltd | Wholesale & retail | 2025 |
| Flame and Crust Pizzas Limited | Hospitality | 2025 |
| Flame District Ltd | Hospitality | 2026 |
| Flame Energy Limited | Professional & scientific | 2019 |
| Flame Fire Protection Ltd | Public administration | 2023 |