| Fire Stop Partitions Limited | Wholesale & retail | 2019 |
| Fire-Construction Limited | Administrative & support | 2024 |
| Fired Earth Holdings Limited | Financial services | 2021 |
| Firelily International Ltd | Professional & scientific | 2023 |
| Fireplaces and Heating Ltd | Construction | 2018 |
| Fireware Limited | Transport & logistics | 2011 |
| First Capitol Limited | Financial services | 2015 |
| First Car Direct Ltd | Wholesale & retail | 2021 |
| First Choice Consulting Ltd | Professional & scientific | 2019 |
| First Choice Garages Ltd | Wholesale & retail | 2026 |
| First Choice Health Limited | Financial services | 2018 |
| First Choice Hire Ltd | Other services | 2017 |
| First Choice Office Solutions Limited | Wholesale & retail | 1997 |
| First Croyland Investment Limited | Extraterritorial | 1960 |
| First Education Limited | Education | 1999 |
| First Pro Builders Limited | Construction | 2022 |
| First Prospect Creative Limited | Information & communication | 2010 |
| First Response Fire Protection and Electrical Limited | Manufacturing | 2003 |
| First Response Security Management Ltd | Administrative & support | 2017 |
| First Response Security Team Limited | Administrative & support | 2012 |
| First-Training Ltd | Wholesale & retail | 2017 |
| FIRST2TRACK Motorsports Limited | Transport & logistics | 2026 |
| Firstbridge Capital Ltd | Real estate | 2015 |
| Firstfind Limited | Professional & scientific | 2003 |
| Firthwells Brickwork Ltd | Construction | 2026 |
| Firwood Tree and Garden Services Ltd | Administrative & support | 2019 |
| Fish Versity Ltd | Agriculture & fishing | 2026 |
| Fisher Investments Limited | Real estate | 1977 |
| Fisher Services Limited | Health & social care | 2024 |
| Fistol Ltd | Information & communication | 2011 |
| Fit Factory 24/7 Ltd | Arts & recreation | 2025 |
| Fitila Limited | Manufacturing | 2026 |
| Fitters to Site Ltd | Construction | 2023 |
| Fitz CAP Ltd. | Real estate | 2015 |
| Fitzanders Ltd | Information & communication | 2026 |
| Fitzgerald Reinforcing Limited | Construction | 2005 |
| FITZROVIA74 Limited | Real estate | 2019 |
| Five Bells Cople Beds Ltd | Hospitality | 2026 |
| Five Bricks Construction Ltd | Real estate | 2018 |
| Five Digit Productions Ltd | Information & communication | 2023 |
| Five Fratelli Ltd | Hospitality | 2019 |
| Five High Ltd | Construction | 2020 |
| Five Rivers Consulting Limited | Professional & scientific | 2003 |
| Five Rivers Corporation Limited | Information & communication | 2013 |
| Five Rivers Dance Academy CIC | Other services | 2025 |
| Five Star Cleaning and Maintenance Ltd | Construction | 2024 |
| Five Star Nails Bedford Limited | Other services | 2023 |
| FIX My Tyre Ltd | Manufacturing | 2019 |
| FIX Your Phone at Home Limited | Other services | 2025 |
| Fixbot Ltd | Construction | 2023 |
| Fizm Ltd | Information & communication | 2024 |
| FJ Logistics Ltd | Transport & logistics | 2025 |
| FJB Electrical Ltd | Construction | 2026 |
| FJR Fit-Out Ltd | Construction | 2020 |
| FKA Global Resources Limited | Wholesale & retail | 2025 |
| FKA Group Services Ltd | Construction | 2023 |
| Flajoy Enterprises Limited | Wholesale & retail | 2024 |
| Flame Contain International Ltd | Construction | 2015 |
| Flamelily Books Limited | Information & communication | 2021 |
| Flames Grill Tavi Ltd | Hospitality | 2024 |
| Flames Musto Ltd | Hospitality | 2026 |
| Flamesafe Heating & Plumbing Limited | | 2010 |
| Flare Holdings Limited | Financial services | 2015 |
| Flare Products Limited | Manufacturing | 1982 |
| Flash Lash Beauty Ltd | Other services | 2025 |
| Flat Management (Beeston) | Professional & scientific | 1985 |
| Flavours Beauty Limited | Wholesale & retail | 2019 |
| Flawless Cleaning Bedford Ltd | Administrative & support | 2025 |
| Fleet Tyres Direct Limited | Wholesale & retail | 2014 |
| Fleetron Consult Ltd | Professional & scientific | 2013 |
| Fleetvolt Limited | Manufacturing | 2025 |
| Fletcher Blake Limited | Information & communication | 2014 |
| Fletcher Contractors Ltd | Construction | 2018 |
| Fletcher Ellam Limited | Professional & scientific | 2014 |
| Fletcherweb Limited | Financial services | 2023 |
| Fleur Trail Ltd | Information & communication | 2025 |
| FLEX2THECORE Fitness Ltd | Arts & recreation | 2019 |
| Flexi Support Limited | Health & social care | 2026 |
| Flexible Training Limited | Education | 2004 |
| Flexihold Limited | Wholesale & retail | 2020 |
| Flexistay Luton Limited | Real estate | 2025 |
| FLI Water Limited | Manufacturing | 1989 |
| Flightcity Limited | Real estate | 1988 |
| Flit Engineering & Storage Limited | Agriculture & fishing | 1965 |
| Flittech Ltd | Information & communication | 2022 |
| Flitwick Accountants Ltd | Professional & scientific | 2019 |
| Flitwick Barbers Limited | Other services | 2023 |
| Flitwick Cricket Club Ltd | Arts & recreation | 2023 |
| Flitwick Flat Roofing Ltd | Construction | 2023 |
| Flitwick Lodge Events Ltd | Arts & recreation | 2022 |
| Flitwick Nail Bar Ltd | Other services | 2024 |
| Flitwick Watermill Locations Ltd | Professional & scientific | 2026 |
| Flix Gymnastics Bedford Limited | Arts & recreation | 2025 |
| Flofast Plumbing & Heating Ltd | Construction | 2012 |
| Floor City Limited | Wholesale & retail | 2000 |
| Floor Heat Supplies Limited | Wholesale & retail | 2024 |
| Floor Heat Systems Ltd | Construction | 2021 |
| Floorscape Interiors Ltd | Construction | 2026 |
| Floortrade Limited | Wholesale & retail | 2006 |
| Floowid Accounting Limited | Professional & scientific | 2021 |