| First Avenue (Office Sales) Limited | Edinburgh | 1971 |
| First Avenue Enterprise Limited | London | 2018 |
| First Avenue Freehold Limited | London | 2002 |
| First Avenue Management Company Limited | Leeds | 2008 |
| First Badge Limited | Skipton | 1919 |
| First Blend Ltd | London | 2025 |
| First Call Business Solutions Limited | Bootle | 2019 |
| First Call Communications Limited | Chorley | 2013 |
| First Call Factors Limited | Eastleigh | 2003 |
| First Call Grab Hire Limited | Gloucester | 2017 |
| First Call Plant Group Limited | Gloucester | 2017 |
| First Call Plant Limited | Gloucester | 2017 |
| First Call Plant Rental Limited | Gloucester | 2017 |
| First Call Resolution Ltd | Manchester | 2023 |
| First Call Stone Supplies Limited | Gloucester | 2017 |
| First Car World Ltd | Sutton | 2022 |
| First Care Homes Limited | Fareham | 2012 |
| First Carton Thyne Ltd | Nottingham | 1938 |
| First Century Holdings Limited | Bournemouth | 2023 |
| First Champion International Limited | England | 2014 |
| First Choice Cleaning Limited | London | 2019 |
| First Choice Computers Limited | Wolverhampton | 2004 |
| First Choice Homes Limited | Oldham | 2019 |
| First Choice Lifts Ltd | Calne | 2012 |
| First Choice PPF Ltd | Bournemouth | 2021 |
| First Choice Training Company Limited | Bournemouth | 2002 |
| First Choice Windows Limited | Benfleet | 2009 |
| First Class Windows, Doors and Conservatories Ltd | Port Talbot | 2025 |
| First Cliq Technologies Limited | Nottingham | 2025 |
| First Corporate Law Services Limited | Bristol | 1997 |
| First Credit Management Limited | Evesham | 2011 |
| First Croyland Investment Limited | Bedford | 1960 |
| First Dawn Developments Ltd | Cheltenham | 2015 |
| First Decommissioning Limited | Aberdeen | 2010 |
| First Director Limited | Bristol | 2000 |
| First Drive Limited | Harrogate | 2011 |
| First E11EVEN Sports Management Limited | Leeds | 2010 |
| First Edition Books Ltd | London | 2014 |
| First Employee Benefits Limited | Leeds | 2025 |
| First Equipment Limited | Cleethorpes | 1998 |
| First Equitable Group Limited | London | 2026 |
| First Equity Nominees Limited | London | 1986 |
| First Event Limited | Leeds | 1999 |
| First Foot Forward Limited | London | 2025 |
| First Formations Ltd | Glasgow | 2014 |
| First Formations Services Ltd | London | 2026 |
| First Home Improvements Ltd | Lenwade | 2021 |
| First Hydrocarbons Limited | Aberdeen | 2016 |
| First IFA Limited | Leeds | 2025 |
| First Instruments Limited | Royston | 2008 |
| First Investment Consulting Limited | Leeds | 2025 |
| First Kicks Football Academy Limited | Billericay | 2020 |
| First Kingsclere Court Management Co. Limited | New Barnet | 1989 |
| First Liberty Service Ltd | Haverfordwest | 2025 |
| First Light Communications Limited | London | 2011 |
| First Light Communities C.I.C. | Exeter | 2015 |
| First London Enterprises Limited | London | 1995 |
| First Media (Holdings) Limited | Louth | 2014 |
| First Medical Finance Limited | Worsley | 2008 |
| First Mobile Solutions Ltd | Daventry | 2010 |
| First Mortgage Shop Limited | Edinburgh | 1997 |
| First Mortgages Limited | Edinburgh | 1999 |
| First Name Ltd | Chesterfield | 2005 |
| First National Corporate Services Limited | Bristol | 1997 |
| First National Direct Limited | Ilford | 2015 |
| First National Motor PLC | London | 1988 |
| First National Plant Rental Limited | Harrogate | 1987 |
| First National Shipping Co. Limited | Manchester | 2019 |
| First National Tricity Finance Limited | London | 1955 |
| First News (UK) Limited | London | 2018 |
| First Nominees Limited | Salford | 2005 |
| First Oak Braintree Investments Limited | London | 2023 |
| First Oak Braintree Limited | London | 2022 |
| First Oak Caerleon Investments Limited | London | 2022 |
| First Oak London Limited | London | 2023 |
| First Option Safety Group Limited | London | 2005 |
| First PAY Limited | London | 2009 |
| First Point Maintenance Limited | London | 2009 |
| First Protection Limited | London | 2002 |
| First Protectors Ltd | London | 2001 |
| First Racing Parts Ltd | Manchester | 2014 |
| First Reallive Ltd | Manchester | 2024 |
| First Rental Limited | Luton | 1998 |
| First Resilience Ltd | Warrington | 2013 |
| First Response Online Ltd | Feltham | 2019 |
| First Response Site Supplies Ltd | Rayleigh | 2010 |
| First Response Tool Hire Limited | Rayleigh | 2011 |
| First Response Training Limited | Pershore | 2015 |
| First Rome Ltd. | London | 2016 |
| First Secretary Limited | Bristol | 1998 |
| First Serve Accountants Limited | Harpenden | 2009 |
| First Stage Sevenoaks Ltd | Sevenoaks | 2024 |
| First State Pizza Company Limited | Banbury | 2002 |
| First Steps Nursery Limited | Warrington | 2001 |
| First Stop Pharmacy Ltd | Glasgow | 2021 |
| First Stop Safety Ltd | York | 2002 |
| First Time Cruises Limited | Plymouth | 2024 |
| First Time Limited | Aberdeen | 2008 |
| First Union Property Company Limited | Camberley | 1997 |
| First United Line Limited | Manchester | 2019 |