| Biovault Family Limited | Plymouth | 2013 |
| Biovault Technical Limited | Plymouth | 2012 |
| Biovelle Ltd | Smethwick | 2025 |
| Bioventora Ltd | Isleworth | 2026 |
| Bioverity Ltd | London | 2020 |
| Biovie Ltd | Portsmouth | 2023 |
| Biovitality Solutions UK Ltd | London | 2024 |
| Biowell Health Ltd | Croydon | 2022 |
| Biowell Performance Medicine Ltd | Croydon | 2025 |
| Biowellness Care Limited | Loughborough | 2025 |
| Bioxatia Limited | London | 2022 |
| Bioxdale Limited | Paddock Wood | 2020 |
| BIP Dental Limited | Cheltenham | 2018 |
| Biped Limited | Middlesbrough | 2017 |
| Bipin Patel Locums Limited | London | 2006 |
| Biplan Limited | Basildon | 2010 |
| Bipolar Peer Project CIC | Sudbury | 2025 |
| Bipolar Scotland | Paisley | 1996 |
| Bipolar UK Ltd | London | 1985 |
| Bipshayl Associates Limited | Nottingham | 2017 |
| BIQ Associates Limited | Cambridge | 1998 |
| Bira Care Homes Limited | Swansea | 2014 |
| Bira Healthy Minds Ltd | Ipswich | 2021 |
| Birakos Ltd | Swindon | 2023 |
| Birama Limited | Slough | 2020 |
| Biranase Healthcare Ltd | Manchester | 2023 |
| Bircan Co Ltd | London | 2020 |
| Birch & Nest Limited | Sheffield | 2025 |
| Birch Assist Limited | Edinburgh | 2009 |
| Birch Care Group Ltd | Gateshead | 2025 |
| Birch Care Ltd | Stockport | 2017 |
| Birch Day Care Ltd | West Bromwich | 2025 |
| Birch Dental Laboratory Limited | Manchester | 2015 |
| Birch Dental Practice Limited | Ellesmere Port | 2014 |
| Birch Green Care Centre Limited | Leicester | 2000 |
| Birch Health & Wellness Limited | Blackburn | 2020 |
| Birch House (Kent) Ltd | Bromley | 2024 |
| Birch House Osteopathic Clinic Limited | Yate, Bristol | 2007 |
| Birch Housing Limited | London | 2014 |
| Birch Lodge Ltd | Northwood Hills | 2025 |
| Birch Medical Ltd. | Ilford | 2015 |
| Birch Psychological Associates Ltd | St. Albans | 2024 |
| Birch Social Limited | Weymouth | 2022 |
| Birch Terrace Dental Ltd | Stoke On Trent | 2018 |
| Birch Tree Care Limited | London | 2018 |
| Birch Tree Practice Ltd | London | 2021 |
| Birch View Health Care Limited | Sheffield | 2023 |
| Birchcourt Limited | Cardiff | 2006 |
| Birchester Care Limited | Peterborough | 2017 |
| Birchester Medicare Services Limited | Oundle | 2022 |
| Birchfield Dental Care Limited | Glasgow | 2020 |
| Birchfield Residential Care Home Limited | Walsall | 2025 |
| Birchgood Limited | Cardiff | 2015 |
| Birchgrove (Ewell) Acquisitions Limited | Woking | 2018 |
| Birchgrove (Godalming) Acquisitions Limited | Woking | 2020 |
| Birchgrove Care Limited | Woking | 2016 |
| Birchgrove Healthcare (Sussex) Limited | Haywards Heath | 2007 |
| Birchgrove Operations Limited | Woking | 2016 |
| Birchington Dental Practice Ltd | London | 2025 |
| Birchlands (Haxby) Limited | Leicester | 2014 |
| Birchley Consultants Limited | St. Helens | 2013 |
| Birchtree Care Housing CIC | London | 2021 |
| Birchview Dental Care Limited | Nairn | 2012 |
| Birchwood Anaesthetic Consultants Limited | Romsey | 2012 |
| Birchwood and Co Case Management Ltd | Sheffield | 2020 |
| Birchwood Care Dixon Ltd | Ulverston | 2025 |
| Birchwood Care Services Limited | | 2003 |
| Birchwood Dental Associates Ltd | Hove | 2019 |
| Birchwood Dental Practice Limited | Walsall | 2008 |
| Birchwood EA Limited | Norwich | 2010 |
| Birchwood Gastroenterology Limited | Dartford | 2019 |
| Birchwood Health Limited | Cardiff | 2004 |
| Birchwood Homecaring Services Limited | Derbyshire | 2000 |
| Birchwood Independence Ltd | Taunton | 2018 |
| Birchwood Priory Medical Limited | Maidenhead | 2016 |
| Birchwood Private Physiotherapy Poole Ltd. | Poole | 2014 |
| Birchwood Radiology Limited | Scunthorpe | 2026 |
| Bircotes Consult Limited | Doncaster | 2019 |
| Bird and Fairley (Dunmow) Limited | Darwen | 2006 |
| Bird and Fairley (Loughton) Limited | Darwen | 2006 |
| Bird Box Gallery CIC | Cambridge | 2024 |
| Bird Healthcare Ltd | London | 2026 |
| Bird Medical Services Limited | Waterlooville | 2018 |
| Bird Mountain Therapy Ltd | Birmingham | 2024 |
| Bird of Paradise Ministries in Rwanda | Bangor | 2011 |
| Bird Therapeutic Services Limited | Macclesfield | 2026 |
| Birdential Limited | Preston | 2025 |
| Birdi Dental Limited | Wilmslow | 2018 |
| Birdi Healthcare UK Ltd | Gravesend | 2024 |
| Birdies Day Nursery Limited | Belfast | 2002 |
| Birdlip House Ltd | Altrincham | 2022 |
| Birdmilk Ltd | Exeter | 2016 |
| Birdseed [Funding] (UK) Ltd | London | 2020 |
| Birdseye Health Care Ltd | London | 2023 |
| Birdsfly Sangstha Limited | London | 2026 |
| Birdsmedical Ltd | London | 2023 |
| Biren Healthcare Limited | Nottingham | 2026 |
| Birkbeck Dentistry Limited | Sidcup | 2013 |
| Birkbeck Natural Health Centre Limited | Kent | 2006 |
| Birkby Dental Care Limited | Huddersfield | 2011 |