| Axcess Marine Contractors(Uk) Ltd | London | 2017 |
| AXE Valley Mining Consultants Limited | Swanage | 2011 |
| Axies Ventures Ltd | London | 2022 |
| Axiom Global Fuels Ltd | London | 2026 |
| Axisnova Technologies Ltd | London | 2026 |
| AXT3N Offshore Ltd | Norwich | 2025 |
| AY OIL International Ltd | London | 2025 |
| AY Technical Services Limited | Glasgow | 2018 |
| Aylesford Heritage Limited | Aylesford | 2013 |
| Azeire Limited | Clapham | 2007 |
| Azimuth Offshore Limited | Exeter | 2005 |
| Azimuth Oilfield Systems Ltd. | Aberdeen | 2009 |
| Azinam South Africa Limited | Clapham | 2018 |
| Azule Energy Exploration (Angola) Limited | London | 1958 |
| Azule Energy Limited | London | 2022 |
| B DJ Robertson Ltd | Elgin | 2025 |
| B J Winton Consultants Limited | Aberdeen | 2020 |
| B Keenan Ltd | Lancashire | 2008 |
| B L Plant Services Limited | Stoke On Trent | 2003 |
| B P Mckernan Contracts Limited | Armagh | 2014 |
| B R Campbell Limited | Montrose | 1998 |
| B Whitt Ltd | Montrose | 2014 |
| B&K Health Mediclean Facility Limited | Slough | 2014 |
| B. B. Drilling Limited | | 1977 |
| B.Mccaffrey & Sons Limited | Enniskillen | 1968 |
| BA Management & Accountancy Services Ltd | Mitcham | 2020 |
| BA Quarries Ltd | Belfast | 2017 |
| Baara - Gold Limited | Aylesbury | 2024 |
| Babetia Functional Fertilizer (Europe) Co., Ltd | Kington | 2020 |
| Bachmann Group Ltd | London | 2018 |
| Back-Up Line Ltd | Newtown | 2014 |
| Badger Resources Ltd | London | 2010 |
| Bag-N-Agg Limited | Norwich | 2015 |
| Bagnall Limited | Co Tyrone | 2005 |
| Baines Instruments Limited | Middlesbrough | 2013 |
| Baird Group(Uk) Limited | Weston Super Mare | 2019 |
| Baird Subsea Ltd. | Aberdeen | 2008 |
| Bakell Ltd | London | 2018 |
| Baker Hughes Limited | London | 1978 |
| Bakewell Reclaimed Stone Limited | Matlock | 2015 |
| Bakken Redux Limited | Middlewich | 2020 |
| Balgownie Geoscience Ltd | Aberdeen | 2020 |
| Ball EYE Quarry Limited | Ripley | 2023 |
| Bally Renewables Limited | Cookstown | 2017 |
| Ballynahinch Fuel Company Ltd | Ballynahinch | 2000 |
| Balmedie Subsea Ltd | Montrose | 2013 |
| Baltor Ltd | Girvan | 2012 |
| Bampton Stone Limited | Royston | 2012 |
| Banaba OIL and GAS Exploration Corp Ltd | London | 2025 |
| Bance Global Teknic Limited | Cambridge | 2024 |
| Banner Contracts (Halnaby) Limited | Darlington | 1993 |
| Bannerman Energy (UK) Limited | London | 2012 |
| Bannerman Projects Limited | Aberdeen | 2025 |
| BAO Ning Plant Nutrition (UK) Ltd | Cambridge | 2026 |
| Baobab Steel Limited | | 2005 |
| Bara Consulting Ltd | Thirsk | 2013 |
| Barclay OIL Services Ltd | Cardiff | 2011 |
| Bardi Design Services Limited | Aberdeen | 2006 |
| Bardo (Midlands) Limited | Peterborough | 1992 |
| Barnston Products Limited | Challenge Way, Blackburn | 1994 |
| Baroque Enterprises Limited | Great Yarmouth | 1989 |
| Barr Projects Ltd | Dundee | 2017 |
| Barra Energy Limited | Aberdeen | 2015 |
| Barrachander Quarry Limited | Cairndow | 2012 |
| Barrack Hill Quarries Limited | Dungannon | 1992 |
| Barracuda Energy Storage Limited | Cardiff | 2020 |
| Barrick Gold (Egypt) 1 Limited | London | 2021 |
| Barrick Gold (Egypt) 2 Limited | London | 2021 |
| Barrick Gold (Egypt) 3 Limited | London | 2021 |
| Barrick TZ Limited | London | 2010 |
| Barrie Wainwright Rigging Services Ltd | Halifax | 2025 |
| Barrix Group Ltd | London | 2026 |
| Barrowell Geoconsultants Ltd | London | 2022 |
| Barry Anthony Wright Limited | Exeter | 2024 |
| Barry Quinn Stoneworks Limited | Maidstone | 2022 |
| Base Metal Company Limited | London | 2015 |
| Base OIL Ltd | London | 2022 |
| Base Vision Holdings Group Ltd | London | 2026 |
| Basic Plant Nutrition PTY Ltd | Coventry | 2024 |
| BAT Construction & OIL Products Trade Corporation Ltd | Bushey | 2023 |
| Batavia OIL Rang Dong Ltd | London | 1999 |
| Bath Stone Company (BSC) Limited | Chipping Norton | 2017 |
| Bath Stone Company Limited | Chipping Norton | 1981 |
| Bathgate Silica Sand Limited | Liverpool | 1916 |
| Bathgate Walker Group Limited | Liverpool | 1964 |
| Bathyal Ltd | Littlehampton | 2022 |
| Bauteil Engineering Ltd. | Glasgow | 2011 |
| Bawejem Limited | | 1986 |
| Baxter Aggregates Limited | Thornton Cleveleys | 2021 |
| Bay Drilling Company Ltd. | Banchory | 2002 |
| Bay Mining Consultants Limited | Hitchin | 2012 |
| Bazel Minerals Ltd | Wigan | 2025 |
| Baztech Ltd | Aberdeen | 2011 |
| BB Projects Ltd | Aberdeen | 2014 |
| BBG Consultants Ltd | Doncaster | 2019 |
| Bbrov Ltd | Stamford | 2022 |
| BCM Engineering Ltd | London | 2019 |
| BCM Group Holding UK Limited | London | 2025 |
| BCS Logistics Ltd | Poole | 2021 |
| Bdms Global Ltd | London | 2014 |