| Prospero Staffing Ltd | Administrative & support | 2025 |
| Protech FSA Solutions Ltd | Construction | 2025 |
| Protech Systems Engineering Ltd | Professional & scientific | 2023 |
| Protecta 365 Limited | Information & communication | 2015 |
| Proteus Leadership Limited | Professional & scientific | 2019 |
| Proud House RTM Company Limited | Households | 2010 |
| Proud to Serve Healthcare Ltd | Health & social care | 2023 |
| Provigilence Services Ltd | Other services | 2025 |
| Prowace Limited | Professional & scientific | 2007 |
| Prowise Estates Ltd | Real estate | 2016 |
| Proxix Ltd | Households | 2024 |
| Prulab Pharma Ltd | Manufacturing | 2017 |
| PS 127-1 Limited | Information & communication | 2019 |
| PS Transport Ltd | Transport & logistics | 2019 |
| PS Windows & Doors Ltd | Construction | 2024 |
| PSB Agency Limited | Transport & logistics | 2026 |
| PSB Products Ltd | Wholesale & retail | 2022 |
| Pscl Limited | Real estate | 2014 |
| PSL Electrical Limited | Construction | 2003 |
| PSW Asset Management Limited | Real estate | 2025 |
| Psychiatric Services Limited | Health & social care | 2006 |
| PTD Developments Ltd | Real estate | 2024 |
| PTK Facilities Management Ltd | Administrative & support | 2020 |
| Puckeridge Limited | Real estate | 2013 |
| Puddle Media Limited | Information & communication | 2024 |
| Puddle PUP UK Limited | Wholesale & retail | 2024 |
| Puffwig Ltd | Real estate | 2019 |
| Puglia Limited | Hospitality | 2014 |
| Pullinn (Emperor) Ltd | Wholesale & retail | 2019 |
| Pullman Construction (London) Limited | Construction | 2016 |
| Pullum Estates Limited | Hospitality | 2025 |
| Pullum Holdings Limited | Financial services | 2022 |
| Pulse Art Designs Limited | Information & communication | 1999 |
| Pulse Motion Production Limited | Information & communication | 2024 |
| Pulse Window Film Ltd | Construction | 2025 |
| Puma Speed Limited | Professional & scientific | 2003 |
| Pundit Consulting Ltd | Information & communication | 2024 |
| Pupilasset Ltd | Information & communication | 2010 |
| Pure Analysis Limited | Professional & scientific | 2017 |
| Pure Essence Collection Ltd | Wholesale & retail | 2016 |
| Pure Excellence Ltd | Health & social care | 2014 |
| Pure Golf Media Limited | Professional & scientific | 2025 |
| Pure Heat Plumbing Ltd | Construction | 2026 |
| Pure Southwest Limited | Other services | 2024 |
| Pure Swiss Aesthetics Ltd | Wholesale & retail | 2014 |
| Purely Land Ltd | Real estate | 2024 |
| Purple Engineering Support Services Limited | Professional & scientific | 2017 |
| Purple Kaart Limited | Real estate | 2015 |
| Purple Maze Ltd | Professional & scientific | 2012 |
| Purple Pond Limited | Real estate | 2019 |
| Purple Rain Investment Management Ltd | Financial services | 2016 |
| Purple Rain Promotions Limited | Administrative & support | 2017 |
| Purple Turkey Limited | Administrative & support | 2013 |
| Purrwell Cattery Ltd | Agriculture & fishing | 2025 |
| Pursuit Accounting and Finance Limited | Administrative & support | 2010 |
| Pursuit Executive Recruitment Ltd | Administrative & support | 2010 |
| Push IT Soho Ltd | Administrative & support | 2010 |
| PUT Capital Ltd | Administrative & support | 2017 |
| Puzzlearning Limited | Information & communication | 2026 |
| PW Alpha Limited | Administrative & support | 2004 |
| PW Building Developments Ltd | Construction | 2017 |
| PW Employment Law Ltd | Professional & scientific | 2015 |
| PW Fairway Limited | Professional & scientific | 2022 |
| PW Quality Consulting Limited | Professional & scientific | 2024 |
| PY Capitals Limited | Financial services | 2025 |
| Q Cheema Ltd Ltd | Health & social care | 2025 |
| Q Digital Limited | Extraterritorial | 2014 |
| Q Internet Limited | Extraterritorial | 2017 |
| Q Manor Ltd | Real estate | 2018 |
| Q-Rev Limited | Administrative & support | 2023 |
| Q360 Limited | Financial services | 2011 |
| Qbit POS Ltd | Wholesale & retail | 2023 |
| QCS Techniques Limited | Professional & scientific | 2018 |
| QD Solutions Ltd | Water & waste | 2018 |
| QE Square Management Limited | Real estate | 2024 |
| QI Project Consultancy Ltd | Professional & scientific | 2013 |
| Qoal UK Ltd | Wholesale & retail | 2024 |
| Qoser Ltd | Hospitality | 2025 |
| Qote Limited | Professional & scientific | 2024 |
| QS4 Projects Limited | Professional & scientific | 2025 |
| QUA Solutions Ltd | Education | 2025 |
| Quality Advice Experts Ltd | Professional & scientific | 2021 |
| Quality Auto Trading Limited | Wholesale & retail | 2011 |
| Quantera Technology Limited | Information & communication | 2025 |
| Quantock Haulage Limited | Professional & scientific | 1984 |
| Quantum Multi-Academy Trust | Education | 2025 |
| Quantus Gallery (London) Limited | Wholesale & retail | 2022 |
| Quantus Gallery Ltd | Wholesale & retail | 2021 |
| Quartz Digital Ltd | Information & communication | 2025 |
| Quay Business Advice Limited | Professional & scientific | 2010 |
| Queens Court (Brentwood) Management Company Limited | Households | 1982 |
| Quercus Management Consulting Limited | Professional & scientific | 2011 |
| Quesey Contract Services Limited | Construction | 2018 |
| Quevedo Equestrian Ltd | Wholesale & retail | 2025 |
| Quick Margin Limited | Administrative & support | 2021 |
| Quick Start IT Limited | Information & communication | 2016 |
| Quickcall M&E Limited | Construction | 2007 |
| Quickpurchase Limited | Real estate | 2007 |
| Quicksilver Management Limited | Hospitality | 2009 |
| Quid Games Ltd | Administrative & support | 2022 |