| Brass Metal Company Limited | London | 2015 |
| Brauncewell Quarries Limited | Sleaford | 1971 |
| Braunton Aggregates Limited | Bideford | 2002 |
| Brazil Iron Limited | London | 2012 |
| Brazil Iron Trading Limited | London | 2010 |
| Brazil Nongprui Silicon Mining Group Chemical Co., Ltd | West Midlands | 2023 |
| Brazilian Nickel Limited | London | 2013 |
| Breamore Technical Services Ltd | Dorchester | 2021 |
| Breedon Cement Limited | Derby | 2012 |
| Breedon Trading Limited | Derby | 1919 |
| Brennan Energy Services Ltd | Godalming | 2020 |
| Brent OIL & GAS Ltd | London | 2015 |
| Bressay Salmon Limited | Glasgow | 1987 |
| Bresson Energy Ltd | London | 2020 |
| Brett Aggregates Limited | Canterbury | 1936 |
| Brett Asphalt Limited | Canterbury | 1962 |
| Brett Davies Limited | Pontypridd | 2019 |
| Brett Fairlop Limited | Canterbury | 1997 |
| Brett Landscaping Limited | Canterbury | 1938 |
| Brett Marine Aggregates Limited | Canterbury | 1965 |
| Brett Paving Limited | Canterbury | 1959 |
| Brewbob Services Ltd | Ossett | 2022 |
| BRH Ltd | Bishopton | 2016 |
| Brian a Miller Limited | Alford | 2016 |
| Brian Bell Geologist Ltd. | Glasgow | 2006 |
| Brian Macgregor & Sons Limited | | 1976 |
| Brian Smith Pipeline & Process Services Ltd | Bellshill | 2014 |
| Brickbat Limited | London | 1997 |
| Brickfile Limited | Stonehaven | 2004 |
| Bridestone & Brydges Limited | Congleton | 2013 |
| Bridge Petroleum 1 Limited | London | 2016 |
| Bridge Petroleum 2 Limited | London | 2016 |
| Bridge Petroleum 3 Limited | London | 2017 |
| Bridge Petroleum 4 Limited | London | 2017 |
| Bridge Petroleum 5 Limited | London | 2017 |
| Bridge Petroleum 6 Limited | London | 2017 |
| Bridge Petroleum Limited | London | 2015 |
| Bridgend Aggregates Limited | Banff | 2000 |
| Bridgestone Mcgroder Quarries Ltd | Newry | 2024 |
| Briggs Drilling Consultancy Ltd | Helston | 2005 |
| Briggs Drilling Holdings Limited | Helston | 2014 |
| Brighton Inspection Ltd | London | 2021 |
| Brilliant Structure Ltd | Loughton | 2024 |
| Brinetech Limited | Chinnor | 2025 |
| Brinklow Biogas Ltd | Near Rugby | 2014 |
| Brinklow Quarry Limited | Tamworth | 2008 |
| Briscotec Ltd | Lowestoft | 2010 |
| Bristo Offshore Ltd | Great Yarmouth | 2015 |
| Bristol Glasgow Belfast and Cardiff Heavy Industries Limited | Leek | 2016 |
| Bristol Mining Ltd | Weybridge | 2016 |
| Britannia Aggregates Limited | Canterbury | 1988 |
| Britannic Oilfield Services Limited | Norwich | 1990 |
| Britannicus Stone Limited | London | 2010 |
| Britestone Capital Limited | Gillingham | 2016 |
| Britguy Trading Ltd | London | 2025 |
| British Aggregates Association | Glasgow | 2000 |
| British Drilling and Freezing Company Limited | Nottingham | 1989 |
| British Salt Limited | Northwich | 2007 |
| British-Nigeria Petroleum OIL and GAS Ltd | London | 2025 |
| Britmines Limited | Birmingham | 2026 |
| Britnrg Limited | Leigh-On-Sea | 2020 |
| Britoil Limited | Aberdeen | 1982 |
| Britwell OIL & Energy Solutions Limited | Manchester | 2025 |
| Brixsom Ltd | Brentford | 2019 |
| BRN Midco Limited | London | 2023 |
| Broadoak Sand and Gravel Company Limited | London | 1950 |
| Broichan Ltd | Inverurie | 2022 |
| Bromfield Sand & Gravel Co. Limited | Ludlow | 1964 |
| Bromsberrow Sand & Gravel Co. Limited | Gloucester | 1974 |
| Brook House Minerals Limited | Whitby | 2018 |
| Brookemead Solutions Limited | Eastbourne | 2002 |
| Brookland Sand & Aggregates Limited | St. Austell | 2009 |
| Brooksby Natural Resources Limited | Loughborough | 1996 |
| Broseley Fireclay Company Limited | Newport | 2004 |
| Broughton Moor Green Slate Quarries Limited(The) | Kirkby In Furness | 1931 |
| Browell Services Ltd | Inverurie | 2026 |
| Brown Bros (Longridge) Limited | Clitheroe | 1959 |
| Brown Clark Group Limited | Ashby-De-La-Zouch | 2004 |
| Browne Offshore Services Ltd | Norwich | 2019 |
| Bruce Cairnrobin Limited | Glasgow | 2015 |
| Bruce Group Limited | Kincardine | 2007 |
| Bruce Plant Limited | Aberdeenshire | 2000 |
| Bruce Quarries Limited | Turriff | 1998 |
| Brucie Drilling Services Ltd | Brechin | 2021 |
| Brutusleaf Limited | Larbert | 2021 |
| Bryan Bell Services Limited | Sheffield | 2015 |
| Brygge Ltd | Edinburgh | 2019 |
| Bryn Aggregates Limited | Hengoed | 2013 |
| Bryn Bach Coal Limited | Llandybie | 1997 |
| Bryn Newydd Colliery Company Limited | Neath | 1966 |
| BSJ Site Engineering Ltd | Dundee | 2008 |
| BSK Projects Ltd | Basingstoke | 2026 |
| BSM Associates Ltd | Peterhead | 2013 |
| Btnsons Consulting Ltd | London | 2021 |
| Bucking Horse Natural Resources Ltd | Weybridge | 2026 |
| Buckland Services Ltd | Norwich | 2021 |
| Buffalo Crow Ltd | Colchester | 2012 |
| Buglass Bio-Fuels Ltd | Aberdaugleddau | 2026 |
| Building Battery Britain Ltd | Lytham St. Annes | 2024 |
| BUK Burkina Faso Limited | London | 2015 |