| Proair Engineers Limited | Energy | 2018 |
| Proap Ltd | Information & communication | 2024 |
| Proartsplus Ltd | Professional & scientific | 2024 |
| Proaudiorecycling Ltd | Wholesale & retail | 2024 |
| Probe Associates Limited | Information & communication | 1997 |
| Probuild Joinery Services Ltd | Construction | 2016 |
| Probury Limited | Professional & scientific | 2000 |
| Procare Fluid Management Ltd | Professional & scientific | 2019 |
| Procast Fencing and Paving Ltd | Manufacturing | 2020 |
| Procia Ltd | Information & communication | 2014 |
| Proco Group Limited | Financial services | 2016 |
| Proco Print Limited | Manufacturing | 1997 |
| Procold Ltd | Manufacturing | 2016 |
| Procqneuro Ltd | Information & communication | 2026 |
| Procter and Co Accountants Ltd | Professional & scientific | 2014 |
| Proctor and Matthews Architects Studio North Limited | Professional & scientific | 2026 |
| Proctor Ceilings Limited | | 1972 |
| Proctor Heating Services Limited | Construction | 1989 |
| Proctor Partnerships (Yorkshire) Limited | Public administration | 2012 |
| Procura Engineering Ltd | Manufacturing | 2015 |
| Procura Ltd | Professional & scientific | 2020 |
| Procure Vehicles Ltd | Wholesale & retail | 2025 |
| Proddow Mackay Legal Limited | Professional & scientific | 2004 |
| Prodigal FOX Ltd | Manufacturing | 2015 |
| Prodigy Union Ltd. | Information & communication | 2023 |
| Prodigy Workforce Ltd | Administrative & support | 2025 |
| Product Minds Ltd | Health & social care | 2021 |
| Production Engineering Research Associates Limited | Professional & scientific | 2016 |
| Prodywus Management Consultancy Limited | Financial services | 2020 |
| Proesque Ltd | Information & communication | 2016 |
| Prof-Care Limited | Health & social care | 2016 |
| Profamilia Investments Limited | Real estate | 2025 |
| Professional Coaching Academy Ltd | Other services | 2020 |
| Professional Lifting Services Limited | Manufacturing | 1985 |
| Professional Maternity Legal Services Ltd | Health & social care | 2024 |
| Professional Security Training Limited | Education | 2025 |
| Professional Service Delivery Ltd | Information & communication | 2023 |
| Professional Software Ltd | Wholesale & retail | 1985 |
| Professor Thompson & Associates Psychological Services Ltd | Health & social care | 2025 |
| Proficient Personnel Ltd | Administrative & support | 2020 |
| Proficit Limited | Construction | 2003 |
| Profile Communication (UK) Limited | Administrative & support | 2002 |
| Profima Ltd. | Real estate | 2007 |
| Proforce Security Services Limited | Professional & scientific | 2007 |
| Program Mara Global Financial Ltd | Information & communication | 2017 |
| Progress House Limited | Wholesale & retail | 2000 |
| Progressive Assets Ltd | Real estate | 2017 |
| Progressive Care (Derbyshire) Limited | Health & social care | 1994 |
| Progressive Care (Holdings) Limited | Financial services | 2007 |
| Progressive Care Group Limited | Financial services | 2019 |
| Progressive Care Limited | Health & social care | 1998 |
| Progressive Care Property Management LLP | | 2017 |
| Progressive Care UK Limited | Professional & scientific | 2006 |
| Progressive Electrical Solutions Ltd | Construction | 2022 |
| Progressive Futures Ltd | Other services | 2025 |
| Progressive Health Care Ltd | Extraterritorial | 2010 |
| Prohms Limited | Health & social care | 2003 |
| Project 226 CIC | Arts & recreation | 2021 |
| Project 304 Ltd | Hospitality | 2020 |
| Project Ak'Ei Limited | Professional & scientific | 2018 |
| Project Batch Ltd | Real estate | 2023 |
| Project Batch Management Ltd | Hospitality | 2023 |
| Project Beach Holdco Limited | Real estate | 2015 |
| Project Buzz | Health & social care | 2010 |
| Project Citizen Limited | Information & communication | 2024 |
| Project Coach Makers LLP | | 2021 |
| Project Devonshire LLP | | 2017 |
| Project Devonshire Management Limited | Real estate | 2017 |
| Project DIG Ltd | Information & communication | 2025 |
| Project Gain Ltd | Education | 2025 |
| Project Goat Holdco Limited | Real estate | 2015 |
| Project Goat Limited | Construction | 2015 |
| Project Granary Holdco Limited | Financial services | 2022 |
| Project Granary Limited | Real estate | 2022 |
| Project House Constructions Ltd | Construction | 2025 |
| Project Jinkss LLP | | 2021 |
| Project Lansdowne Ltd | Hospitality | 2024 |
| Project Loop Ltd | Wholesale & retail | 2025 |
| Project M Ltd | Administrative & support | 2012 |
| Project PG Limited | Information & communication | 2024 |
| Project Presents Ltd | Wholesale & retail | 2019 |
| Project Republica Bidco Limited | Information & communication | 2016 |
| Project Republica Topco Limited | Information & communication | 2016 |
| Project Rose 1 Limited | Real estate | 2016 |
| Project S Consulting Limited | Information & communication | 2023 |
| Project Sandwich Limited | Hospitality | 2023 |
| Project X Micropubs Limited | Hospitality | 2024 |
| Projectic Solutions Ltd | Information & communication | 2018 |
| Projectorgames Limited | Information & communication | 2008 |
| Projects and Services Ltd | Construction | 2008 |
| Prokem (Corrosion Protection) Ltd. | Construction | 2009 |
| Prokopē Property Solutions Limited | Real estate | 2021 |
| Prolific Productions Limited | Information & communication | 1998 |
| Prolink Transport Limited | Transport & logistics | 2026 |
| Prolux Cars Ltd | Wholesale & retail | 2025 |
| Prolux Homes Ltd | Real estate | 2024 |
| Prometheus Blinds Limited | Construction | 2016 |
| Promo Clothing Ltd | Wholesale & retail | 2022 |
| Promoting Health UK C.I.C. | Health & social care | 2024 |
| Promotional Clothing Company Limited | Wholesale & retail | 2010 |