| One One Five Ltd | Real estate | 2025 |
| One-Light (UK) Limited | Wholesale & retail | 2013 |
| Oneday Agency Limited | Wholesale & retail | 2010 |
| Onezone London Ltd | Construction | 2012 |
| Online Music Exams Limited | Information & communication | 2021 |
| Onyx Electrical Solutions Limited | Construction | 2022 |
| Opencage Data Limited | Information & communication | 2015 |
| Opens App Ltd | Information & communication | 2022 |
| Opensauce Ltd | Professional & scientific | 2025 |
| Opkan Limited | Real estate | 2016 |
| Opterum Ltd | Information & communication | 2024 |
| ORA Developments Ltd | Real estate | 2026 |
| Orange & Green Plumbing & Heating Ltd | Construction | 2015 |
| Orchard INT. Ltd. | Wholesale & retail | 2023 |
| Orion Properties London Ltd | Real estate | 2016 |
| Orma Solutions Ltd | Professional & scientific | 2014 |
| Oscars Catering Services Limited | Hospitality | 2016 |
| Ourdrobe Ltd | Wholesale & retail | 2025 |
| Oval Products Limited | Wholesale & retail | 2011 |
| Overarch Creative Ltd | Professional & scientific | 2021 |
| Ovoq Ltd | Information & communication | 2026 |
| Owton Manor Holdings Ltd | Administrative & support | 2020 |
| Ozpa Limited | Hospitality | 2023 |
| Ozrod Ltd | Financial services | 2025 |
| P a M Developments Limited | Construction | 2020 |
| P J Mear Limited | Construction | 2009 |
| P J Valves Group Limited | Financial services | 2023 |
| P L Plant Limited | Administrative & support | 2011 |
| P Lovett Building Services Ltd | Construction | 2015 |
| P M P Roofing Services Ltd | Construction | 2015 |
| P&V Partners LLP | | 2010 |
| P.B. Plumbing Limited | Construction | 2015 |
| P.G. Oakden & Sons Limited | Financial services | 2023 |
| P.J. Pipe & Valve Co. Limited | Manufacturing | 1976 |
| P.S. Marketing Services Limited | Administrative & support | 2004 |
| P.S. Online Styling Ltd | Other services | 2020 |
| Paddock Close Residents Company Limited | Households | 2025 |
| Palestine Trauma Centre (UK) | Health & social care | 2009 |
| Palfinger Tail Lifts Limited | Wholesale & retail | 1971 |
| Palladium Consulting Engineers Limited | Professional & scientific | 2010 |
| Palm Incorporated Limited | Wholesale & retail | 2023 |
| Pamraine Properties Limited | Extraterritorial | 2015 |
| Panda Strategy Limited | Real estate | 2022 |
| Papagayo Limited | Real estate | 2016 |
| Papic Limited | Arts & recreation | 2022 |
| Paradigm Ventures Limited | Financial services | 2020 |
| Parameter Strategy Limited | Professional & scientific | 2012 |
| Paramount Community Projects Limited | Construction | 2017 |
| Paramount Landscapes Limited | Professional & scientific | 2009 |
| Parentpals Ltd | Information & communication | 2024 |
| Paril Limited | Hospitality | 2019 |
| Park Lodge (Garston) Freeholders Limited | Households | 2018 |
| Park Lodge (Garston) Management Limited | Households | 1991 |
| Parker-Litjens Properties Ltd | Real estate | 2015 |
| Parkes Incorporated Limited | Construction | 1996 |
| PARKINGLIFTS4GARAGES.COM Limited | Wholesale & retail | 2016 |
| Parsley Horticultural Software Ltd | Information & communication | 2020 |
| Parsonage Barns Construction Ltd | Construction | 2006 |
| Parthenon Consulting Limited | Information & communication | 2021 |
| Partizan Brewing Limited | Manufacturing | 2012 |
| Passer Studio Ltd | Information & communication | 2014 |
| Pathfinder PM Ltd | Information & communication | 2007 |
| Patlyn Ltd | Wholesale & retail | 2026 |
| Patrick Dunne Props Limited | Information & communication | 2014 |
| Paul Johnson Consulting Limited | Professional & scientific | 2018 |
| Paul Patrick Ltd | Wholesale & retail | 2021 |
| Paulcable Ltd | Professional & scientific | 2023 |
| Paws & Pulse Ltd | Other services | 2026 |
| Pawsitive Strides Limited | Professional & scientific | 2021 |
| Paxform Properties Limited | Real estate | 1976 |
| PAY N Transfer Limited | Financial services | 2026 |
| Paylaterr UK Limited | Financial services | 2024 |
| Pbatch Consulting Limited | Wholesale & retail | 2016 |
| Pdaa Ltd | Real estate | 2021 |
| PDC (Hertford) Ltd | Professional & scientific | 2016 |
| PDC Conveyancing Limited | Professional & scientific | 2020 |
| PDS Group Limited | Construction | 2016 |
| Pearce Hayter Developments Limited | Real estate | 2021 |
| Pearce Manor Residents Association Limited | Households | 1989 |
| Pearl Milk Bar Ltd | Hospitality | 2022 |
| Pearlgate Property Management Limited | Households | 1982 |
| Pelle Aesthetics Limited | Health & social care | 2016 |
| Pender and Dale Limited | Wholesale & retail | 2021 |
| Peniel & Partners Ltd | Manufacturing | 2023 |
| Penrith Estates Limited | Real estate | 2009 |
| Pension Savvy Ltd | Professional & scientific | 2023 |
| Penta World Series Limited | Arts & recreation | 2024 |
| Pentastone Ltd | Professional & scientific | 2026 |
| Peoplecore Advisory Ltd | Professional & scientific | 2026 |
| Perfect Plumbing Group Ltd | Administrative & support | 2019 |
| Perfect World Landscape Ltd | Administrative & support | 2019 |
| Perfection Corporate Services Limited | Transport & logistics | 1996 |
| Performing Pets Limited | Arts & recreation | 2016 |
| Peristyle Properties Ltd | Real estate | 2015 |
| Perroperties Ltd | Real estate | 2019 |
| Peter Robinson Electrical Services Limited | Construction | 2014 |
| Petrocapital Resources Limited | Financial services | 2006 |
| Pevington Autos Limited | Manufacturing | 2020 |
| PFS Homes Ltd | Real estate | 2019 |
| Pgrsa Ltd | Education | 2015 |