| Biohackpro Ltd | London | 2026 |
| Bioko Global Solutions Ltd | Croydon | 2022 |
| Biolacuna Holdco 1 Limited | Wantage | 2021 |
| Biolacuna Holdco 2 Limited | Wantage | 2021 |
| Biolacuna Management Co 1 Ltd | Wantage | 2026 |
| Bioleap Trustee Limited | Cambridge | 2022 |
| Biolinx Global Limited | Coventry | 2025 |
| Biological Preparations Group Limited | Caerphilly | 2014 |
| Biologicals International Limited | London | 2022 |
| Biologiques Staves Ltd | London | 2025 |
| Biomanagement Systems Limited | Dartford | 2018 |
| Biomass Group Limited | London | 2020 |
| Biomass Holdings Ltd | London | 2020 |
| Biomass UK NO.4 Limited | London | 2019 |
| BIOME10 Limited | London | 2021 |
| Biomecann PLC | London | 2019 |
| Biomedical Contractor Solutions Ltd | London | 2022 |
| Biomedx Limited | Worcester | 2013 |
| Biomonde Limited | Bridgend | 2021 |
| Bionex Ltd | Newbury | 2020 |
| Bionex Science & Engineering Ltd | London | 2026 |
| Bionic Bull Holdings Limited | Hertford | 2020 |
| Bionic Development Ltd | London | 2025 |
| Bionic Financial Services Limited | London | 2011 |
| Bionical Solutions Group Limited | Derbyshire | 2018 |
| Bionicare Limited | Hitchin | 2022 |
| Bionicvale UK Limited | Manchester | 2014 |
| Bionome Group Limited | London | 2022 |
| Bionome Technology Limited | London | 2020 |
| Bionova Holding Limited | East Grinstead | 2024 |
| Biopharma Credit PLC | London | 2016 |
| Biopharma Development Ltd | London | 2001 |
| Biopower (Hartlepool) Holdings Limited | Middlesbrough | 2017 |
| Bioregional Learning Trust | Totnes | 2024 |
| Biorenix Limited | Ipswich | 2025 |
| Bios-Footprint Ltd | Swindon | 2020 |
| Bioscapes Group Limited | York | 2026 |
| Bioscience Equity Partners Limited | London | 2022 |
| Bioscience Managers Digital Limited | London | 2019 |
| Bioscience Managers UK Limited | London | 2017 |
| Bioscript Group Limited | Macclesfield | 2015 |
| Bioscript Holdings Limited | Macclesfield | 2021 |
| Bioscript Limited | Macclesfield | 2021 |
| Bioscript Midco 1 Limited | Macclesfield | 2021 |
| Bioscript Midco 2 Limited | Macclesfield | 2021 |
| Biospectrum Holdings Limited | Newark | 2025 |
| Biosphere Topco Limited | Whiteley | 2023 |
| Biosynergy Holdings Limited | Cambridge | 2020 |
| Biosynth Group Limited | Newbury | 2021 |
| Biotech Capital Limited | London | 2021 |
| Biotech Innovations Ltd | Sheffield | 2023 |
| BIOTECH4 Limited | Gainsborough | 2020 |
| Bioticnrg Ltd | Wellingborough | 2022 |
| Biotrace Property Holdings Ltd | Warrington | 2025 |
| Biotrack Technologies Limited | Tonbridge | 2025 |
| Biovittal Limited | London | 2024 |
| Biovyteam Limited | Belfast | 2020 |
| Bioworld Holdings Limited | Cheadle | 2025 |
| Biozone Scientific Group Limited | Cardiff | 2020 |
| BIP Consulting UK Holdings Limited | London | 2020 |
| BIP Enterprises Limited | Bradford | 2016 |
| BIP Industries Limited | Addlestone | 2001 |
| Biplane Bidco (UK) Limited | London | 2015 |
| BIR Group Investments Ltd | Birmingham | 2022 |
| BIR Group Limited | Birmingham | 2017 |
| BIR Investments Group Limited | Southgate | 2017 |
| Bira Capital Ltd | Swansea, Wales | 2025 |
| Bira Care Group Limited | Swansea | 2025 |
| Bira Group Limited | Swansea | 2019 |
| Biral Holdings Limited | Bristol | 2014 |
| Biraln Holdings Ltd | Wetherby | 2025 |
| Biran Holdings Ltd | Leamington Spa | 2022 |
| Birbeck (Liftech) Limited | Pitcombe | 2019 |
| Birch Contracts Group Limited | Lichfield | 2019 |
| Birch Faraday Capital Ltd | London | 2021 |
| Birch Financial Group Limited | Luton | 2018 |
| Birch Financial Solutions Limited | Coggeshall | 2011 |
| Birch Fitted Furniture Limited | Coalville | 2006 |
| Birch Gardens Company Limited | Ballymena | 2015 |
| Birch Hill Capital Ltd | Belfast | 2016 |
| Birch Investment Group Limited | Worcester Park | 2020 |
| Birch Lake Investments Limited | Bangor | 2019 |
| Birch Mortgage & Financial Solutions Limited | Doncaster | 2014 |
| Birch Valley Holdings Limited | Driffield | 2015 |
| Birch Wharf Holdings Limited | Barking | 2026 |
| Birch's Holdings Ltd | Cambridge | 2025 |
| Birchall Gregory Ltd | Chislehurst | 2021 |
| Birchall Holdings Ltd | Sherborne | 2020 |
| Birchall Investments Ltd | Liverpool | 2026 |
| Birchcore Limited | London | 2018 |
| Birchcrown Finance Limited | | 1981 |
| Birchden Holdings Limited | London | 2018 |
| Birchendel Holdings Limited | Stafford | 2016 |
| Birches Brow Holdings Limited | Chesterfield | 2022 |
| Birchester Care Holdings Limited | Peterborough | 2018 |
| Birchfield Epsom Limited | Stockport | 2013 |
| Birchfield Estates Ltd | London | 2006 |
| Birchfield Holdings Limited | Newtown | 2024 |
| Birchforest Holdings Limited | Lichfield | 2017 |
| Birchgate Investments Limited | Broadstairs | 2015 |