| Formet Limited | Newbridge | 2002 |
| Formex Chemicals Co., Ltd | Beckenham | 2015 |
| Formforce UK Limited | Northampton | 2017 |
| Formigal Projects Limited | Newbury | 2018 |
| Formitalia UK Limited | London | 2008 |
| Formitrite (Company Formations) Limited | St. Albans | 1995 |
| Formosity Limited | Reading | 2011 |
| Formpave Limited | Northampton | 2016 |
| FORMS4U Limited | Newcastle Upon Tyne | 2007 |
| Formsafe Systems Limited | Chester | 2019 |
| Formscape Group Limited | Reading | 2003 |
| Formsolve Ltd | Folkestone | 2022 |
| Formtec International Trade Co., Limited | Kington | 2005 |
| Formula Air Racing Limited | Waltham Abbey | 1989 |
| Formula Autocentres Limited | Stevenage | 2014 |
| Formula Holdings Ltd | Cheshire | 2020 |
| Formula One (FOH) Holdings Limited | London | 2011 |
| Formula One Limited | London | 2001 |
| Formula One Productions Limited | London | 2008 |
| Formula One Promotions and Administration Limited | London | 2012 |
| Formula One Publishing Limited | London | 2002 |
| Formula One Race Car Engineering Limited | London | 1984 |
| Formula One Trade Windows (Wiltshire) Limited | Walsall | 2026 |
| Formula One World Travel Limited | London | 2010 |
| Formula One Yachts Limited | Harrow | 2008 |
| Formula Plus Autocentres Limited | Stevenage | 2014 |
| FORMULA1.COM Limited | London | 2008 |
| Formulas for Success Limited | North East Lincolnshire | 1989 |
| Fornax Finance Ltd | Amersham | 2023 |
| Fornham Pigs Limited | Hessle | 2011 |
| Foro Industry Co., Ltd | Gillingham | 2017 |
| Foro Studio Home Ltd | London | 2025 |
| Forosophobia Limited | London | 1871 |
| Forrest & Fraser Ltd | Eastleigh | 2022 |
| Forrest Group Limited | Glasgow | 2018 |
| Forrest Jackson Limited | Harrogate | 2025 |
| Forrestchef Berget Invest Limited | London | 2023 |
| Forrestchef Berget Limited | London | 2023 |
| Forrester Boyd Company Secretarial Services Limited | | 1988 |
| Forrester Boyd Outsourced Business Solutions Limited | Grimsby | 2022 |
| Forrester Holdings (Zimbabwe) Limited | London | 1982 |
| Forrow Law Limited | Rochester | 2013 |
| Forse Consultants Company Limited | Shropshire | 1998 |
| Forsell Holding Limited | London | 2021 |
| Forstal Farm Limited | Ashford | 2025 |
| Forster Pneumatic Copper Industry Ltd | Beckenham | 2021 |
| Forsters Shelfco 336 Limited | London | 2012 |
| Forsters Shelfco 338 Limited | London | 2013 |
| Forsyth Management Limited | Ilford | 1987 |
| Forsyth Trustees Limited | Rothes | 2014 |
| Forsyth Whitehead & Associates Limited | Boroughbridge | 1991 |
| Forsythe & Kayee Limited | London | 1979 |
| Fort 1961 Limited | South Shields | 2014 |
| Fort William Assets Limited | Manchester | 2014 |
| Fortalist Ltd | Sutton | 2024 |
| Fortchin Enterprise Limited | Beckenham | 2017 |
| Forte Dance & Performing Arts Ltd | Ware | 2022 |
| Forte Education Group Limited | Doncaster | 2022 |
| Forte Maritime Security Limited | Walthamstow | 2016 |
| Forte's Rhyl Ltd | Conwy | 2018 |
| Fortecho Limited | London | 2015 |
| Fortegate Inter Ltd | Ipswich | 2026 |
| Fortem Drink Ltd | Bristol | 2021 |
| Fortem Food Ltd | Bristol | 2021 |
| Fortem Gbbs Ltd | Bristol | 2011 |
| Fortem Holdings Limited | Letchworth Garden City | 1975 |
| Fortexa Nexaro Trading Ltd | Manchester | 2026 |
| Fortgale Ltd | Salford | 2001 |
| Forth & TAY Property Company Limited | Edinburgh | 1964 |
| Forth and District Initiative | Lanark | 2013 |
| Forth Emergency Services Ltd | Radstock | 2020 |
| Forth Estate Management Limited | Midlothian | 1990 |
| Forth Limited | Stirling | 2002 |
| Forth Management Limited | Stirling | 2002 |
| Forth Ports Trustees Limited | Midlothian | 1991 |
| Forth PPP Limited | Stirling | 2001 |
| Forth Services Limited | Stirling | 2002 |
| Forth Utilities Limited | Stirling | 2002 |
| Forth Valley Vets Limited | Fife | 2013 |
| Forthbridge Films Limited | London | 2015 |
| Forthill Management Company Limited | Ballyclare | 1999 |
| Forthkirk Limited | Edinburgh | 1999 |
| Forthmoor Ltd | Salford | 2002 |
| Fortify Property Services Ltd | Redruth | 2016 |
| Fortifynet Cybersecurity Group Ltd | Harrogate | 2022 |
| Fortingall 1961 Limited | Falkirk | 2014 |
| Fortis and SOL Limited | Manchester | 2026 |
| Fortis Brushwell Limited | Cults | 2016 |
| Fortis Cardiff Limited | Cheltenham | 2013 |
| Fortis Coating Solutions Limited | Cambridge, | 2021 |
| Fortis Contract Lifting Limited | Redditch | 2021 |
| Fortis Cranes and Lifting Limited | Redditch | 2021 |
| Fortis Electrical Solutions Limited | Cambridge, | 2021 |
| Fortis EV Ltd | Purfleet | 2022 |
| Fortis Partitions Ltd | Canvey Island | 2019 |
| Fortis Remote Technology Limited | Broughton In Furness | 2010 |
| Fortitudo Investments Ltd | London | 2024 |
| Fortium Accountants Ltd | Barnet | 2026 |
| Fortium Ltd | Bridgend | 2006 |
| Fortium Personal Development Limited | Belfast | 2016 |