| Base International Limited | London | 2025 |
| Base Serviced Apartments Ltd | Liverpool | 2013 |
| Base Tech Ltd | Chapel Allerton | 2025 |
| Base Technologies Holdings Limited | Strand | 2018 |
| Basecamp Financial Planning Limited | Matlock | 2022 |
| Basecamp Southern Limited | Eastleigh | 2023 |
| Baseera Group Finance Limited | Luton | 2025 |
| Basel Actuarial Services Limited | Glasgow | 2016 |
| Basel Analytics Ltd | London | 2015 |
| Basel UK Acquisition Co. Limited | Hemel Hempstead | 2022 |
| Baseline Office Holdings Limited | Goole | 2023 |
| Baseline Real Estate Limited | Chelmsford | 2016 |
| Basement (Yorkshire) Limited | Cleckheaton | 2026 |
| Basement Waterproofing Services (UK) Holdings Limited | Tredegar | 2025 |
| Basesettom Ltd | Banbury | 2021 |
| Basesound Services Limited | Salisbury | 1993 |
| Basetek (Holdings) Limited | Ipswich | 2008 |
| Basf Agricultural Solutions UK Limited | Stockport | 2022 |
| Basf Pensions Trustee Limited | Stockport | 1997 |
| Bash Build Limited | Ossett | 2022 |
| Bash Street Developments Ltd | Preston | 2022 |
| Basha Holdings Limited | Hornchurch | 2024 |
| Bashir Group Ltd | Luton | 2019 |
| Bashkal Investments Limited | Edmonton | 2018 |
| Bashur Travel Limited | Sheffield | 2025 |
| Basi & Basi Consulting Limited | Southam | 2011 |
| Basic Capital Investments Limited | London | 2019 |
| Basic Prime Limited | Croydon | 2023 |
| Basico Manufacturing Ltd | Longfield | 2020 |
| Basics Claims Limited | Middlesbrough | 2000 |
| Basie I (RS502R1) Limited | London | 2020 |
| Basik Money Ltd | Glasgow | 2016 |
| Basil Accounts Holdings Ltd | Reading | 2026 |
| Basil E. FRY & Co. Limited | Leatherhead | 1979 |
| Basil Grange Property Limited | Liverpool | 2019 |
| Basil ST Properties Ltd | Sale | 2021 |
| Basildon Borough Enterprises Limited | Basildon | 2020 |
| Basileia Investment Holdings (UK) Limited | London | 2022 |
| Basileia Investment Ventures (UK) Limited | London | 2022 |
| Basilica Group Ltd | London | 2025 |
| Basilica Hospitality Ltd | London | 2022 |
| Basilica Wealth Advisory Ltd | Faringdon | 2026 |
| Basing Hill Industrial Securities Limited | London | 1962 |
| Basinghall (MB) Limited | London | 2022 |
| Basinghall (MH) Limited | London | 2022 |
| Basinghall (SB) Limited | London | 2022 |
| Basinghall (SH) Limited | London | 2022 |
| Basinghall Holdings Ltd | Woking | 2022 |
| Basinghall Partners Limited | London | 2017 |
| Basinghall Properties 1 Limited | London | 2022 |
| Basinghall Properties 2 Limited | London | 2022 |
| Basingstoke Bidco Limited | Chineham, Basingstoke | 2022 |
| Basingstoke Topco Limited | Chineham, Basingstoke | 2022 |
| Basis Capital Ltd | Bath | 2024 |
| Basis Capital Markets UK Limited | London | 2015 |
| Basis House Ltd | Eastbourne | 2018 |
| Basis Vault Ltd | London | 2026 |
| Basit Financial Services Limited | Cardiff | 2022 |
| Bask Holding Limited | London | 2025 |
| Baskerville Group Ltd | Glasgow | 2025 |
| Baskerville Securities Ltd | Sunderland | 2017 |
| Baskerville Ventures Limited | Dudley | 2012 |
| Basket Case Media Limited | Andover | 2024 |
| Baskeyfield Corporate Holdings Limited | Newcastle | 2025 |
| Baslow Holdings | Norwich | 2024 |
| Baslow Insurance Services Holding Company Limited | Sheffield | 2007 |
| Baslow Insurance Services Limited | Bakewell | 2007 |
| BASLOW8 Ltd | Leatherhead | 2024 |
| Basma Wealth Management Limited | London | 2020 |
| Bason Holdings Ltd | Bromley | 2020 |
| Baspharm Limited | London | 2013 |
| Basques (Midlands) Limited | Stafford | 2024 |
| Basran Holdings Ltd | Wolverhampton | 2022 |
| Basrt Ltd | Mansfield | 2023 |
| Bass & Toti Limited | Romford | 2020 |
| Bass & West Holdings Ltd | Milton Keynes | 2021 |
| Bass Group Limited | Peterborough | 2020 |
| Bass Investments | London | 2023 |
| Bass Lift Holdings Limited | Worcester | 2004 |
| Bass Trading Ltd | St. Neots | 2024 |
| Bassa Holdings Ltd | Blackburn | 2026 |
| Bassanio Ventures Limited | Bedford | 2022 |
| Basse-Pointe Advisors Limited | London | 2017 |
| Bassett Crockford Holdings Ltd | Tenby | 2023 |
| Bassett Enterprises Ltd | London | 2016 |
| Bassett House School 2 Ltd | London | 2020 |
| Bassett Trust Limited | Alton | 1931 |
| Bassettco Limited | Lincoln | 2014 |
| Bassetts Financial Consultants Limited | London | 2004 |
| Basseyville Ltd | London | 2026 |
| Bassford Financial Services Limited | Lichfield | 2024 |
| Bassingham Investments Ltd | Lincoln | 2024 |
| Bassline Property Holdings Limited | Birmingham | 2019 |
| Basso Associates UK Limited | London | 2004 |
| Basswood UK Limited | London | 2018 |
| Bastas Solutions Ltd | London | 2018 |
| Bastenburgh Capital Limited | London | 2023 |
| Basteones Holdco Limited | London | 2025 |
| Bastet Wealth Management Ltd | Leigh-On-Sea | 2024 |
| Bastian Capital Limited | Leicester | 2025 |