| A B Steel Structures Ltd | Kingswinford | 2019 |
| A B T Plumbing & Heating Ltd | Guildford | 2018 |
| A B Test & Elec Solutions Ltd | Derby | 2025 |
| A B Utilities Ltd | London | 2018 |
| A B Veares Limited | Romford | 2012 |
| A B W Services Limited | Hertfordshire | 2004 |
| A B Webb Construction Ltd | Liskeard | 2025 |
| A B Wells Projects Ltd | Lincoln | 2018 |
| A B Windows and Home Improvements Ltd | Birmingham | 2015 |
| A B Windows Limited | Westbury | 2019 |
| A B Wooden Gates and Garage Doors Ltd | Willenhall | 2022 |
| A B Woodflooring Limited | London | 2016 |
| A B Woods Limited | Nottinghamshire | 2007 |
| A Bailey Carpentry & Joinery Limited | Banbury | 2014 |
| A Bailey Joinery Ltd | Nelson | 2021 |
| A Bailey Plumbing & Heating Ltd | Birmingham | 2015 |
| A Baker Construction & SON Ltd | Littlehampton | 2025 |
| A Bala Construction Ltd | Worcester Park | 2026 |
| A Ball Design Ltd | Wirral | 2013 |
| A Bamber Groundworks Ltd | Grantown-On-Spey | 2025 |
| A Banwell Limited | Bath | 2006 |
| A Barber Services Ltd | Tonbridge | 2012 |
| A Bardhi Construction Ltd | Luton | 2023 |
| A Barker Electrical Ltd | Kingston Upon Hull | 2023 |
| A Barlow Brickwork Limited | Preston | 2024 |
| A Barnes Electrical Ltd | Dalton In Furness | 2003 |
| A Bate Building Contractor Limited | Whitchurch | 2010 |
| A Bath Property Investments Limited | Southall | 2025 |
| A Beament Limited | New Milton | 2010 |
| A Beamish Limited | Lowestoft | 2002 |
| A Beattie (Keswick) Limited | Cockermouth | 2004 |
| A Beatty Brickwork Limited | London | 2003 |
| A Beaumont Plastering & Dry-Lining Ltd | Bingley | 2020 |
| A Beck Plumbing & Heating Ltd | Waterlooville | 2015 |
| A Beckett Electrical Limited | Grimsby | 2016 |
| A BEE Contracts Limited | Northampton | 2025 |
| A BEE Electrical Limited | Lancashire | 2007 |
| A BEE Investment Limited | London | 2020 |
| A Belciu Construction Ltd | London | 2015 |
| A Bell Construction ( UK ) Ltd | Worcester | 2026 |
| A Bell Electrical Limited | Leicester | 2021 |
| A Bell Plumbing and Maintenance Ltd | Great Yarmouth | 2026 |
| A Bentley Limited | Halifax | 2005 |
| A Better Build (Derby) Limited | Derby | 2012 |
| A Better Choice for Property Development Limited | Ashford | 2018 |
| A Better Drain Flow Ltd | Reading | 2004 |
| A Bici Fixing Ltd | London | 2016 |
| A Bickerton Plasterers Limited | Glasgow | 2025 |
| A Bilion Brick Ltd | London | 2020 |
| A Billington Electrical Limited | Preston | 2007 |
| A Binns Electrical (Testing) Ltd | Leigh On Sea | 2020 |
| A Binns Electrical Ltd | Leigh-On-Sea | 2014 |
| A Birch Electrics Ltd | Chorley | 2022 |
| A BIT of Chaos Theory Limited | Pontefract | 2026 |
| A BIT on the Side (SW) Limited | Radstock | 2008 |
| A Black Contracts Ltd | Craigavon | 2019 |
| A Black Roofing Limited | Northwich | 2019 |
| A Blacklock Floor Screeding Ltd | Bishop Auckland | 2025 |
| A Bland Construction Ltd | Burntwood | 2019 |
| A Blue (UK) Limited | Finchley | 2012 |
| A Bogucki Electrical Ltd | Southall | 2024 |
| A Boiler 4 U Ltd | Plymouth | 2015 |
| A Bolger Plastering Limited | Borehamwood | 2014 |
| A Bolton Limited | Reading | 2008 |
| A Bond Lighting Ltd | Banbury | 2022 |
| A Bond Plumbing and Heating Limited | Tiverton | 2025 |
| A Booth Plastering Contractors Limited | Oldham | 2004 |
| A Booth Plumbing Ltd | Retford | 2016 |
| A Boss Development Limited | Stourbridge | 2019 |
| A Bounce IS Ltd | Congleton | 2022 |
| A Bowry Limited | London | 2020 |
| A BOY From the RAF Limited | London | 2018 |
| A Brand Builders Ltd | Newmarket | 2022 |
| A Brassett Limited | Torquay | 2014 |
| A Bravo Electrical Ltd | Leeds | 2019 |
| A Bray General Builder Limited | Falmouth | 2005 |
| A Brennan Construction Ltd | Bromley | 2011 |
| A Brew Brickwork Limited | Ely | 2019 |
| A Brice Electrical Ltd | Bristol | 2014 |
| A Brick Project Constructions Ltd. | Uxbridge | 2023 |
| A Bridge Groundworks Ltd | Diss | 2020 |
| A Bright Solution UK Limited | Swansea | 2012 |
| A Bro's Property Services Ltd | London | 2019 |
| A Broadhead Services Ltd | Chorley | 2018 |
| A Brockwitz Builders Ltd | Harrow | 2013 |
| A Brookes Construction Ltd | Shifnal | 2018 |
| A Brooks Construction Limited | London | 2020 |
| A Brooks Decorators Ltd | London | 2023 |
| A Brooks Painters & Decorators Limited | Oldham | 2012 |
| A Brothers Construction Limited | London | 2016 |
| A Brown Builders Holdings Ltd | Barnet | 2013 |
| A Brown Contracting Services Limited | Grimsby | 2018 |
| A Brown Property Solutions Ltd | Wigan | 2017 |
| A Bruce (Building) Ltd | Caithness | 2003 |
| A Bruce Hastie Electrical Contractor Ltd | Selkirk | 2020 |
| A Brumwell Plastering Ltd | Consett | 2018 |
| A Brush Above the Rest Limited | Newbury | 2009 |
| A Brushstroke Away Ltd | London | 2023 |
| A Build & Construction Ltd | Pinner | 2025 |
| A Build & Create@Space Limited | Liverpool | 2016 |