| QH (Potten END) Limited | Construction | 2021 |
| QH (Stevenage) Limited | Construction | 2024 |
| Qiswa Hub Ltd | Wholesale & retail | 2025 |
| QLBR8 Ltd | Professional & scientific | 2021 |
| Qode Ltd | Wholesale & retail | 2026 |
| QSC Heating & Plumbing Ltd | Construction | 2026 |
| Qsurg Limited | Health & social care | 2009 |
| Quadragina ISD Limited | Other services | 2017 |
| Quaid Building Services Ltd | Construction | 2015 |
| Qualified Manpower Ltd | Construction | 2013 |
| Qualis Building Consultancy Limited | Construction | 2017 |
| Quality Connect Limited | Wholesale & retail | 2017 |
| Quality Construction (Surrey) Limited | Construction | 2002 |
| Quality Impact Limited | Education | 2010 |
| Quality of Life Supported Living Limited | Health & social care | 2026 |
| Quantara Advisory Limited | Administrative & support | 2026 |
| Quantoptics Ltd | Professional & scientific | 2024 |
| Quantum IS UK Ltd | Information & communication | 2013 |
| Quantum Leapers Limited | Professional & scientific | 2022 |
| Quantum Removals Ltd | Water & waste | 2021 |
| Quantumics.Ai Ltd | Information & communication | 2019 |
| Quasality Holdings Limited | Information & communication | 2026 |
| Quebec Court Freehold Limited | Real estate | 2010 |
| Queen of Spades Gardening Company Ltd | Administrative & support | 2016 |
| Queenbee Nursery Limited | Health & social care | 2003 |
| Queenswood Homes Contractors Limited | Construction | 2019 |
| Questpark Properties Limited | Real estate | 2024 |
| Quests Makkah Tours Limited | Administrative & support | 2025 |
| Quetrax Limited | Professional & scientific | 2013 |
| Quetzal Energy Services Ltd | Professional & scientific | 2021 |
| Quick Accounting Solution Ltd | Financial services | 2023 |
| Quick Currency Exchange Limited | Financial services | 2012 |
| Quick Picks International Limited | Wholesale & retail | 2015 |
| Quick Response Drain & Plumbing Service 24/7 Ltd | Construction | 2026 |
| Quick Spin Launderette Ltd | Other services | 2026 |
| Quickon Ltd | Construction | 2026 |
| Quicksilver Design Limited | Construction | 1995 |
| Quinnsis Limited | Households | 2021 |
| Quint Education Limited | Administrative & support | 2014 |
| Quintell UK Limited | Administrative & support | 2018 |
| Quizumab Ltd | Education | 2026 |
| QWH Holdings Limited | Financial services | 2021 |
| QWH Property Limited | Real estate | 2021 |
| Qyliq Limited | Information & communication | 2026 |
| R & a Investment Properties Ltd | Real estate | 2021 |
| R & D Textiles Limited | Wholesale & retail | 2020 |
| R & S Property Associates Limited | Real estate | 2010 |
| R & S Property Investments Limited | Real estate | 2009 |
| R & S Superstores Limited | Wholesale & retail | 2016 |
| R B Suite Supported Living Ltd | Health & social care | 2025 |
| R C Anderson Services Ltd | Administrative & support | 2010 |
| R Greene (Renewables) Limited | Professional & scientific | 2011 |
| R J Property Solutions Limited | Real estate | 2016 |
| R K L Services Limited | Construction | 2008 |
| R L Property Rentals Limited | Real estate | 2022 |
| R Myers & Co Limited | Other services | 2013 |
| R P R Contractors Limited | Construction | 2004 |
| R Q P Properties Limited | Real estate | 2014 |
| R Rajput Ltd | Real estate | 2026 |
| R S Creations Limited | Information & communication | 2012 |
| R&B Assistance Ltd | Construction | 2023 |
| R&D Build Ltd | Construction | 2025 |
| R&D Builder Ltd | Construction | 2018 |
| R&J Valeting Limited | Administrative & support | 2024 |
| R&K Bathrooms Ltd | Construction | 2016 |
| R&K Hirani Limited | Construction | 2015 |
| R&K Investment Property Ltd | Real estate | 2023 |
| R&L Trade Ltd | Wholesale & retail | 2023 |
| R&N Healthcare Ltd | Wholesale & retail | 2015 |
| R&N Removal Services Ltd | Transport & logistics | 2025 |
| R&S Cleaners Ltd | Administrative & support | 2023 |
| R-Dental Ltd | Administrative & support | 2024 |
| R-Digi UK Ltd | Information & communication | 2025 |
| R-Health Ltd | Health & social care | 2023 |
| R-U-Mobile Ltd | Wholesale & retail | 2012 |
| R. Nadler Limited | | 1973 |
| R. S. Electrical Edgware Ltd | Construction | 2017 |
| R.A.W.T Events Limited | Other services | 2008 |
| R.J. Auto (London) Limited | Wholesale & retail | 2015 |
| R.M. Europe Limited | Administrative & support | 1998 |
| R2LEAD Limited | Administrative & support | 2020 |
| R2M Services Limited | Construction | 2024 |
| Rachben Ltd | Administrative & support | 2018 |
| Rachel Konits Limited | Health & social care | 2019 |
| Rachtech Consulting Limited | Professional & scientific | 2025 |
| Radbourne Court (Stanmore) Management Company Limited | Households | 2010 |
| Radclive Ltd | Real estate | 2016 |
| Radetal Ltd | Health & social care | 2022 |
| Radha Krishna Limited | Administrative & support | 2014 |
| Radha Raman Limited | Health & social care | 2023 |
| Radhaverse Ltd | Wholesale & retail | 2025 |
| Radiance Medical LED Aesthetics Ltd | Health & social care | 2025 |
| Radiant Clinic Ltd | Other services | 2026 |
| Radiant Stylerz Limited | Other services | 2026 |
| Radiantcare Diagnostics Ltd | Health & social care | 2023 |
| Radlett Home Needs Ltd | Wholesale & retail | 2022 |
| Radlor Limited | Professional & scientific | 2025 |
| Radnor Court London W2 Limited | Other services | 2002 |
| Rado Building & Maintenance Limited | Construction | 2015 |
| Radomsko Ltd | Administrative & support | 2025 |