| PVS Electrical Ltd | Energy | 2025 |
| Pvsso Limited | Wholesale & retail | 2024 |
| PVX Studios Ltd | Information & communication | 2026 |
| PW Dental Limited | Health & social care | 2023 |
| PW Investments Inc Limited | Real estate | 2018 |
| PW Landscaping Ltd | Other services | 2026 |
| PWC Consultancy Ltd | Professional & scientific | 2021 |
| PX Capital Limited | Financial services | 2023 |
| PX Consulting Limited | Information & communication | 2017 |
| PXS CW Ltd | Information & communication | 2017 |
| PYE London Limited | Professional & scientific | 1972 |
| PYH Properties Ltd | Real estate | 2025 |
| Pyra London Limited | Information & communication | 2025 |
| Pyramid Developments Ltd | Real estate | 2023 |
| Pyrantis Ltd | Information & communication | 2025 |
| PZ Construction Design Ltd | Construction | 2017 |
| PZ Homes Ltd | Real estate | 2023 |
| Pérpetua Watch Company, London Ltd | Wholesale & retail | 2024 |
| Q & T Gifts Ltd | Wholesale & retail | 2022 |
| Q & T Properties Ltd | Real estate | 2020 |
| Q Intelligent Security Ltd | Information & communication | 2011 |
| Q&C Services Limited | Administrative & support | 2022 |
| Q.P.T. (UK) Limited | Real estate | 1987 |
| Q2 Locs Parlour Limited | Other services | 2020 |
| Q7 Consultants Ltd | Information & communication | 2020 |
| Q7 Group Holdings Limited | Information & communication | 2024 |
| QA Automotive Ltd | Wholesale & retail | 2025 |
| QA Management Ltd | Professional & scientific | 2024 |
| Qaboli Ltd | Hospitality | 2025 |
| Qadery Lettings Limited | Real estate | 2023 |
| Qahwaty Cafe Ltd | Hospitality | 2025 |
| Qaiza Limited | Education | 2024 |
| Qalam Limited | Information & communication | 1999 |
| Qalines Ltd | Professional & scientific | 2016 |
| Qalma Ltd | Information & communication | 2025 |
| QAN Investments Limited | Financial services | 2025 |
| Qberry Properties Ltd | Real estate | 2023 |
| Qbotik Digital Limited | Information & communication | 2023 |
| QC Projects London Limited | Construction | 2021 |
| QD Boulevard Dental Limited | Health & social care | 2022 |
| QD Horsham Ltd | Health & social care | 2023 |
| QD the Crossways Limited | Real estate | 2023 |
| QD Wimbledon Limited | Health & social care | 2022 |
| Qedigital UK Limited | Information & communication | 2025 |
| Qfixx Ltd | Information & communication | 2020 |
| Qfonic Technology Distribution Network Limited | Wholesale & retail | 2005 |
| QFR Limited | Administrative & support | 2014 |
| QH Solutions Ltd | Other services | 2024 |
| Qing HUA Chinese School Charitable Trust | Education | 1993 |
| QIX Solutions Limited | Extraterritorial | 2008 |
| QLC Tuition Ltd | Education | 2026 |
| Qmetric Interiors Ltd | Construction | 2016 |
| QMS Practice Limited | Extraterritorial | 2008 |
| QNC Consulting (London) Limited | Professional & scientific | 2026 |
| QRS Health Screening and Training Ltd | Health & social care | 2017 |
| QRT Solutions Ltd | Financial services | 2023 |
| QS Properties Ltd | Real estate | 2019 |
| QS Wizards Limited | Professional & scientific | 2022 |
| Qtraining & Building Ltd | Construction | 2019 |
| Quadact Limited | Extraterritorial | 1992 |
| Quadbite Limited | Information & communication | 2023 |
| Quaddy Creative Ltd | Professional & scientific | 2025 |
| Quadedge Accountants Ltd | Professional & scientific | 2023 |
| Quadgem Limited | Information & communication | 1993 |
| Quadra Developments Limited | Administrative & support | 2017 |
| Quadra-Lock Limited | Information & communication | 2026 |
| Quadripple Ltd | Information & communication | 2024 |
| Qualifiedphysio Limited | Health & social care | 2018 |
| Quality Auto Cars Ltd | Wholesale & retail | 2024 |
| Quality Builds Ltd | Construction | 2021 |
| Quality Cake Mirela Ltd | Manufacturing | 2022 |
| Quality Dental Albion Limited | Health & social care | 2018 |
| Quality Dental Fulham Ltd | Health & social care | 2020 |
| Quality Dental Practices Ltd | Health & social care | 2016 |
| Quality Dental Properties Ltd | Real estate | 2016 |
| Quality Dental Worthing Ltd | Health & social care | 2020 |
| Quality Food & Wine Ltd | Wholesale & retail | 2016 |
| Quality Foods Retails Ltd | Wholesale & retail | 2020 |
| Quality Homecare Services Ltd | Health & social care | 2019 |
| Quality Products Ltd | Wholesale & retail | 2026 |
| Quality Recycling Solutions Ltd | Water & waste | 2004 |
| Quality Tools & Bearing Centre (UK) PVT Limited | Wholesale & retail | 2022 |
| Quanta Maths - Pinner LLP | | 2024 |
| Quantile Solutions Ltd | Financial services | 2018 |
| Quantity Surveying Solutions Limited | Professional & scientific | 2013 |
| Quantm Solutions AI Ltd | Information & communication | 2025 |
| Quantum 25 Ltd | Construction | 2020 |
| Quantum Air & Sea Limited | Transport & logistics | 2003 |
| Quantum Bits Ltd | Information & communication | 2021 |
| Quantum BLU Limited | Professional & scientific | 2012 |
| Quantum Leap Advisory Ltd | Professional & scientific | 2024 |
| Quantum Leap Technologies (Holdings) Limited | Professional & scientific | 2017 |
| Quantum Leap Technologies Limited | Professional & scientific | 2014 |
| Quantum PI Limited | Wholesale & retail | 2025 |
| Quantum Property Acquisitions Ltd | Financial services | 2017 |
| Quantum Realty LLP | | 2023 |
| Quantum Remap Ltd | Wholesale & retail | 2023 |
| Quantum Technologies Solution Ltd | Information & communication | 2008 |
| Quantus 2021 Limited | Construction | 2021 |
| Quantus Gifts Ltd | Wholesale & retail | 2026 |