| Book Deal Limited | Manchester | 2022 |
| Book Events South Limited | Portsmouth | 2019 |
| Book Industry Communication Limited | London | 1991 |
| Book Library Limited | Castleford | 2018 |
| Book Medical Limited | Ipswich | 2018 |
| Book My Laundry Ltd | Uxbridge | 2026 |
| Book Nextup Ltd | London | 2025 |
| Book of YOU C.I.C. | Ruthin | 2011 |
| Book Plus Limited | London | 2025 |
| Book Technologies Inc. (GET2 Taxi Group) Corporation Limited | Bradford | 2025 |
| Book Tokens Limited | London | 1943 |
| Book-Keeping Services (Scotland) Ltd. | East Lothian | 2001 |
| Booka Bay Limited | Scarborough | 2022 |
| Bookalet Ltd | Bedford | 2019 |
| Bookapparel Ltd | London | 2025 |
| Bookaspark Ltd | Llanelli | 2024 |
| Bookaway UK Limited | London | 2024 |
| Booked for YOU Ltd | Hertfordshire | 2026 |
| Booker Avenue Gents Ltd | Liverpool | 2024 |
| Bookfellers Limited | Manchester | 2026 |
| Bookham Beauty Limited | Leatherhead | 2021 |
| Booking Services International Limited | Manchester | 1984 |
| Bookish App Limited | Leicester | 2023 |
| Bookkeeper's Detox Ltd | Halstead | 2022 |
| Bookmakers Afternoon Greyhound Services Limited | London | 1967 |
| Bookmarked Ltd | London | 2024 |
| Bookone Limited | London | 2014 |
| Books Bundle Ltd | London | 2024 |
| Booktasters Ltd | London | 2026 |
| Bookyourstylist Limited | Barnet | 2024 |
| Boolberg Ltd | London | 2020 |
| Boom Beauty Limited | London | 2020 |
| Boom Boom Netball Limited | London | 2018 |
| Boom Business Ltd | London | 2019 |
| Boom Event Planners Ltd | Berkhamsted | 2019 |
| Boom Hair Design Ltd | Malton | 2016 |
| Boom Hair Limited | Basildon | 2025 |
| Boom Online Marketing Limited | Derby | 2010 |
| Boom Project Holdings Limited | Derby | 2011 |
| Boombastic Braids Ltd | London | 2023 |
| Boomday Ltd | Glasgow | 2019 |
| Boomerang Carnets Ltd | London | 2014 |
| Boomerang Dogs Ltd | Caerphilly | 2021 |
| Boomi Ltd | Northolt | 2014 |
| Booming Games (UK) Limited | Milton Keynes | 2015 |
| Boomrang E Solutions & Services Private Ltd | Chertsey | 2016 |
| Boomslang Media Ltd | Upminster | 2017 |
| Boomsticks Limited | Wolverhampton | 2012 |
| Boomting Bunting Limited | Halesworth | 2024 |
| Boon Aesthetics Limited | Maidstone | 2021 |
| Boon Beauty Ltd | Bushey | 2025 |
| Boon Health and Beauty Therapies Ltd | Totton | 2023 |
| Boon RUK SA Thai Therapy Limited | York | 2021 |
| Boon Training Academy Limited | Leicester | 2025 |
| Boon.Hair Ltd | Taunton | 2019 |
| Boone & Last Ltd | London | 2020 |
| Boone Design Limited | Bury St. Edmunds | 2007 |
| Boongate Hand Car Wash Ltd | Peterborough | 2017 |
| Boonge Media Ltd | London | 2021 |
| Boonies Ltd | Sandwich | 2022 |
| Boons Ltd | Nottinghamshire | 2005 |
| Boons Management Company (Plymouth) Limited | Plymouth | 1988 |
| Boonwag Limited | Brighton Marina | 2017 |
| Booon Ltd | London | 2024 |
| Boop Petcare Limited | Basingstoke | 2019 |
| Boopie Snoots Limited | Dundee | 2025 |
| Boos Barber Alton Limited | Alton | 2025 |
| Boosche Supplements Ltd | Swansea | 2024 |
| Boosh Hairdressers Limited | Swansea | 2015 |
| Boosh Ltd | Edinburgh | 2003 |
| Boost 4 Life Ltd | St Helens | 2020 |
| Boost AID Ltd | London | 2025 |
| Boost Felixstowe Ltd | Felixstowe | 2000 |
| Boost Lifestyle Ltd | Buckingham | 2020 |
| Boost Limit Development Limited | Barnsley | 2021 |
| Boost of Whitchurch Limited | Whitchurch | 2025 |
| Boost Optimisation Ltd | London | 2024 |
| Boost Payments Limited | Glasgow | 2022 |
| Boost Your Performance Ltd | Belfast | 2020 |
| Booste Ltd | Ruislip, | 2025 |
| Boostech UK Limited | Market Drayton | 2022 |
| Boosted EGO Ltd | Stockton-On-Tees | 2026 |
| Boosted Payments Limited | Glasgow | 2025 |
| Booster Marketing Agency Ltd | London | 2025 |
| Bootcamp UK JDS Limited | Barnstaple | 2017 |
| Booters Barbers Limited | Plymouth | 2026 |
| Booth & Sons Garden Specialists Ltd | Manchester | 2022 |
| Booth Contract Services Limited | Derby | 2021 |
| Booth Nation Limited | London | 2008 |
| Booth Plant Company Holdings Limited | Warrington | 2020 |
| Boothfairy Partnership Ltd | Swindon | 2023 |
| Boothferry Barber Limited | Hessle | 2019 |
| Boothomatic Limited | York | 2018 |
| Booths Family Funeral Services Ltd | Heanor | 2021 |
| Booths Window Cleaning Contractors Limited | Newport Pagnell | 1988 |
| Boothville Services Limited | Northampton | 2024 |
| Boothwood Boarding Kennels & Cattery Limited | Rishworth | 2005 |
| Bootiki Beauty Salon Ltd | Blandford Forum | 2018 |
| Bootle Together CIC | Bootle | 2025 |
| Booworks Ltd | Motherwell | 2011 |