| Britannia Risk Management Limited | London | 2026 |
| Britannia Saxon Holding Limited | London | 2025 |
| Britannia Saxon International Limited | London | 2026 |
| Britannia Steam Ship Insurance Association Limited(The) | London | 1876 |
| Britannia Windows (Holdings) Limited | Clevedon | 2025 |
| Britannia's Gold Limited | London | 2016 |
| Britannic & Commonwealth Investment Company Limited | London | 2020 |
| Britannic Capital Limited | Harrogate | 2019 |
| Britannic Investment Management Limited | Harrogate | 2019 |
| Britannic Investments Iraq Limited | Middlesex | 2012 |
| Britannic Money Investment Services Limited | Birmingham | 1987 |
| Britannic Place Financial Management Limited | Worcester | 2006 |
| Britannic Place Holdings Limited | Worcester | 2021 |
| Britannic Wealth Limited | Wolverhampton | 2013 |
| Britannica Homes Ltd | Abingdon | 2023 |
| Britax Childcare Pensions Trust Limited | Andover | 2006 |
| Britbridge Holdings Ltd | London | 2025 |
| Britcol Limited | Aberdeen | 2017 |
| Britcyp Group Limited | Walthamstow | 2018 |
| Brite Advisors Limited | Trowbridge | 2019 |
| Brite Drinks Ltd | London | 2021 |
| Brite Holdings (Scotland) Limited | Glasgow | 2011 |
| Brite Holdings and Investments Ltd. | Glasgow | 2018 |
| Brite Motoring Limited | Harrow | 2018 |
| Brite Vision Ltd | Sheffield | 2016 |
| Britel Fund Nominees Limited | London | 1983 |
| Britel Fund Trustees Limited | London | 1982 |
| Britel Holdings Limited | London | 2019 |
| Britelight Investments | Birmingham | 2017 |
| Britelite Home Improvement Group Limited | London | 1993 |
| Britgrocer International Holdings Ltd | Newton Aycliffe | 2015 |
| Britgrowth Limited | Oxford | 2017 |
| Brith Holdings Ltd | Sevenoaks | 2022 |
| British & American Investment Trust PLC | London | 1947 |
| British Airways 777 Leasing Limited | Harmondsworth | 2003 |
| British Airways Pension Services Limited | Harmondsworth | 1995 |
| British Airways Pension Trustee (NO. 2) Limited | Harmondsworth | 2002 |
| British Airways Pension Trustees Limited | Harmondsworth | 1948 |
| British Amalgamated Theatres Limited | London | 1929 |
| British American Tobacco (2009 PCA) Limited | London | 2009 |
| British American Tobacco (2009) Limited | London | 2009 |
| British American Tobacco Peru Holdings Limited | London | 2003 |
| British Arab Commercial Bank PLC | | 1972 |
| British Asphalt and Bitumen Limited | Newtownabbey | 1931 |
| British Aviation Insurance Company Limited | London | 1930 |
| British Business Access Lending Limited | Sheffield | 2026 |
| British Business Aspire Holdco Ltd | Sheffield | 2014 |
| British Business Bank PLC | Sheffield | 2013 |
| British Business Finance Ltd | Sheffield | 2014 |
| British Business Financial Services Ltd | Sheffield | 2014 |
| British Business Investments Ltd | Sheffield | 2014 |
| British Caribbean Ltd | Battersea | 2019 |
| British Danubian Trade Development Company Limited | Bromley | 1946 |
| British Engineering Services Bidco Limited | Warrington | 2020 |
| British Engineering Services Finco 1 Limited | Warrington | 2020 |
| British Engineering Services Midco Ltd. | Warrington | 2020 |
| British Engineering Services Topco 1 Limited | Warrington | 2020 |
| British Engines (UK) Limited | Newcastle Upon Tyne | 2010 |
| British Engines Holdings Limited | Newcastle Upon Tyne | 2023 |
| British Engines Limited | Newcastle Upon Tyne | 2010 |
| British Ensign Limited | Horsham | 2018 |
| British Foreign & Colonial Limited | London | 1934 |
| British GAS Insurance Limited | Windsor | 2008 |
| British Green Finance Limited | High Wycombe | 2009 |
| British Guarantee Trust Limited | Pinner | 1945 |
| British Insurance Brokers' Association | London | 1977 |
| British International Investment Overseas Limited | London | 1999 |
| British International Investment PLC | London | 1999 |
| British Juggling CIC | Margate | 2025 |
| British Life Ltd | London | 2005 |
| British Linen Leasing (London) Limited | Edinburgh | 1986 |
| British Patient Capital Limited | Sheffield | 2018 |
| British Pearl Finance Limited | London | 2017 |
| British Pearl Group Limited | London | 2015 |
| British Rail Pension Trustee Company Limited | London | 1981 |
| British Reserve Insurance Company Limited | London | 1935 |
| British Smaller Companies VCT PLC | Leeds | 1995 |
| British Smaller Companies VCT2 PLC | Leeds | 2000 |
| British Technology Investments Limited | London | 2019 |
| British Tissues (Wrexham) Limited | Harrow, | 1966 |
| British WAX (Holdings) Limited | Redhill | 2013 |
| British Wool Marketing Board Pensions Trustee Limited | Bradford | 2008 |
| Britmar (UK) Limited | London | 2007 |
| Britmar Limited | London | 2000 |
| Britmet Group Holdings Limited | Banbury | 2023 |
| Britmet Holdings Limited | Banbury | 2012 |
| Britnaire Limited | Ilford | 2007 |
| Britnell Group Ltd | Basildon | 2024 |
| Britnell Holdings Limited | Leamington Spa | 2021 |
| Britnell Limited | Orpington | 2022 |
| Britnep Financial Services Ltd | London | 2021 |
| Britnep Lending Solutions Limited | London | 2025 |
| Britpark Leisure Group Limited | Wisbech | 2021 |
| Britplas (EOT) Limited | Warrington | 2024 |
| Britplas Group Limited | Warrington | 2019 |
| Britrade Limited | Cavendish Square | 2008 |
| Brits Merks UK Limited | Harrow | 2023 |
| Brits Pitz Limited | Doncaster | 2021 |
| Brittain Holdings International Limited | London | 2025 |
| Brittain Investment Group Ltd | Uxbridge | 2026 |