| Barth-Haas UK Limited | Tonbridge | 2000 |
| Bartham Press (Watford) Limited | Luton | 1984 |
| Bartholdi Limited | Cardiff | 1961 |
| Bartholomew Guitars Ltd | Southampton | 2021 |
| Barti RUM Ltd | Milford Haven | 2018 |
| Bartington Forge Limited | Northwich | 2002 |
| Bartington Instruments Limited | Witney | 1985 |
| Bartkus Composites Limited | Ely | 2020 |
| Bartlams Fitted Bedrooms Limited | Great Barr | 2003 |
| Bartlet Bidco Limited | Woking | 2017 |
| Bartlett DE Choc Ltd | Ringwood | 2024 |
| Bartlett Engineering (South Wales) Limited | Port Talbot | 1992 |
| Bartlett Formwork Ltd | Inverness | 2020 |
| Bartlett Solutions Ltd | Reading | 2015 |
| Bartley Glass & Windows Limited | Halesowen | 2002 |
| Bartley Industries Limited | Northamptonshire | 1964 |
| Bartley Mill Fine Foods Limited | Frant | 1991 |
| Bartola Limited | London | 2017 |
| Bartoline International Limited | Rochdale | 2022 |
| Bartoline Limited | Brighton | 1912 |
| Barton Aluminium Foundries Limited | Leamington Spa | 2015 |
| Barton Architects Limited | Umberleigh | 2021 |
| Barton Bespoke Ltd | Umberleigh | 2025 |
| Barton Blakeley Technologies Limited | Harpenden | 2016 |
| Barton Cold-Form (UK) Limited | Gloucester | 2009 |
| Barton Conduits Limited | Leamington Spa | 2015 |
| Barton Dynamic Industrial Co., Ltd. | London | 2021 |
| Barton Engineering & Export Limited | Whitstable | 1964 |
| Barton Engineering Limited | Leamington Spa | 2015 |
| Barton Fabrications Limited | Bristol | 1987 |
| Barton Fine Foods Limited | Stockport | 2008 |
| Barton Firtop Engineering Co Limited | Kidderminster | 1973 |
| Barton FOX Ltd | Lytham St. Annes | 2002 |
| Barton Furniture Limited | Long Eaton | 2016 |
| Barton Green Services Limited | Burton-On-Trent | 2016 |
| Barton Group Limited | Leamington Spa | 2015 |
| Barton Haven Boatyard Limited | Barton-Upon-Humber | 2014 |
| Barton House Brewing Company Limited | Okehampton | 2010 |
| Barton Industrial Services Limited | Heron Road | 1986 |
| Barton Marine Equipment Limited | Whitstable | 1986 |
| Barton OIL Burner Services Limited | Cambridge | 2017 |
| Barton Precision Property Limited | Nottingham | 1965 |
| Barton Sheds and Fencing Ltd | Manchester | 2024 |
| Barton Site Services Limited | Corby | 2021 |
| Barton Timber Company Limited | Essex | 1945 |
| Barton Tubes Limited | Leamington Spa | 2015 |
| Barton Windows Limited | Manchester | 1986 |
| Bartonbutcher Ltd | Coventry | 2026 |
| Bartondale Engineering Company Limited | Swansea | 1986 |
| Bartons Bakehouse Limited | Stockport | 2023 |
| Bartons Yard Limited | Woodbridge | 2023 |
| Bartorelli Ltd | Newton Abbot | 2011 |
| Bartram International Ltd | Brighton | 1995 |
| Bartram Manufacturing Limited | Sandy | 2007 |
| Bartram Timber Frame Limited | Sandy | 2014 |
| Barugzai Ltd | Bradford | 2019 |
| Barum and Dewar Limited | Glasgow | 1996 |
| Barum Engines Ltd | Barnstaple | 2016 |
| Barvick Engineering Limited | Henstridge | 2002 |
| Barvik Ltd | Reading | 2018 |
| Barvue Ltd | Birmingham | 2022 |
| Barwell Embroidery Services Limited | Leicester | 2006 |
| Barwell Global Limited | St. Ives | 2008 |
| Barwell Spares & Service Limited | Kempston | 2009 |
| Barwest Fabrication Limited | Northampton | 2003 |
| Barwick Carpentry Contractors Limited | Rochester | 2018 |
| Barwick Engineering Limited | Stansted | 2007 |
| Barwick Signs Limited | Grendon | 2010 |
| Barwise and Wong Limited | Liverpool | 1982 |
| Barwood Lock and Door Services Limited | Ware | 2015 |
| Barwoods Bedrooms Limited | Hyde | 2001 |
| Barworkbenches Ltd | Atherstone | 2025 |
| Barzillai Hingley & Sons Limited | Cradley Heath | 1951 |
| Barzy's Ltd | London | 2004 |
| BAS Wagstaff Ltd | Manchester | 1970 |
| Bas-Ip Distribution Ltd | London | 2019 |
| Basad Marble London Ltd | London | 2017 |
| Basalt Distillery Ltd | Bushmills | 2020 |
| Basalt Technologies UK Limited | Wing | 2015 |
| Basalt World Holdings Ltd | Brighton | 2023 |
| Basarab Services Ltd | London | 2020 |
| Base and Gold Limited | Purfleet | 2016 |
| Base B Ltd | London | 2023 |
| Base Concepts Ltd | Gosport | 2025 |
| Base Control Systems Ltd | Watford | 2016 |
| Base Controls Ltd | Shoreham By Sea | 2021 |
| Base Design Ltd | Essex | 2007 |
| Base Electrics Ltd | Plymouth | 2009 |
| Base Formula Limited | Melton Mowbray | 2003 |
| Base Handling Products Ltd | Crickhowell | 2001 |
| Base Homecare Ltd | Liverpool | 2019 |
| Base Infotech Ltd | London | 2021 |
| Base Intrinsic Ltd | Chester | 2014 |
| Base Kitchen Limited | Liverpool | 2026 |
| Base Layer Skincare Limited | London | 2025 |
| Base Lighting Ltd | Plymouth | 2010 |
| Base Line Solving Limited | Dagenham | 2016 |
| Base Logic Ltd | New Malden | 2011 |
| Base Manufacturing Limited | Leicester | 2012 |
| Base Materials Limited | Whetstone | 2002 |