| Opratr Ltd | Professional & scientific | 2025 |
| OPS Lead PH Ltd | Professional & scientific | 2024 |
| OPT4MOBILITY Ltd | Wholesale & retail | 2002 |
| Optical Analytics Limited | Professional & scientific | 2017 |
| Optima Care Holdings Limited | Health & social care | 2014 |
| Optima Care Limited | Health & social care | 1992 |
| Optima Care Shine London Limited | Health & social care | 2015 |
| Optima HCI Limited | Health & social care | 2019 |
| Optimum Design & Consultancy Limited | Professional & scientific | 2015 |
| Optymal Ltd | Professional & scientific | 2023 |
| Opus Energy Products Limited | Manufacturing | 2023 |
| Orange Atlas Ltd | Professional & scientific | 2021 |
| Orangetree Enterprises Ltd | Financial services | 2011 |
| Orca Recruitment Ltd | Administrative & support | 2013 |
| Orion Sales and Trading Ltd | Wholesale & retail | 2019 |
| Orlinspect Ltd | Professional & scientific | 2014 |
| Ormea Ltd | Administrative & support | 2026 |
| Ornbo Limited | Information & communication | 2021 |
| Orrsome Limited | Real estate | 2020 |
| Orsi Gold Ltd | Arts & recreation | 2025 |
| Orton Vision Ltd | Information & communication | 2014 |
| Ostara Productions Limited | Professional & scientific | 2013 |
| Osteopathic Health Limited | Health & social care | 2002 |
| Otter Projects Limited | Information & communication | 2014 |
| Outbenz Ltd | Financial services | 2015 |
| Outside the Box Properties Limited | Other services | 2020 |
| Override Software Limited | Wholesale & retail | 2019 |
| Oxum Estates Limited | Real estate | 2025 |
| Oxum Limited | Financial services | 2025 |
| Oxygen Research Limited | Professional & scientific | 1998 |
| Ozcode Limited | Information & communication | 2020 |
| Pacific Retail Systems Limited | Information & communication | 2004 |
| Pacsmart Ltd. | Wholesale & retail | 2025 |
| Paddock Picturehouse Ltd | Arts & recreation | 2018 |
| Padel Surge Ltd | Education | 2026 |
| PAG General Trading Company Limited | Administrative & support | 2016 |
| Paggarwal Pharma Limited | Public administration | 2025 |
| Palliser Dwyer Ltd | Professional & scientific | 2019 |
| Palmcom Limited | Information & communication | 2014 |
| Palmdale Motors Limited | Wholesale & retail | 2005 |
| Palmmerce Limited | Wholesale & retail | 2026 |
| Pals Messenger Limited | Professional & scientific | 2018 |
| Panacea Growth Partners Ltd | Professional & scientific | 2023 |
| Paperpost Film Ltd | Information & communication | 2023 |
| Paradigm Teddington Ltd | Other services | 2021 |
| Parasoul Ltd | Information & communication | 2013 |
| Paria Executive Ltd | Real estate | 2023 |
| Park Lane Shopfitters Limited | Wholesale & retail | 1976 |
| Park Lane Stables RDA | Agriculture & fishing | 2014 |
| Park Road Surgery Limited | Health & social care | 2018 |
| Park Street Residents Limited | Real estate | 2007 |
| Partyworks Ltd | Wholesale & retail | 2025 |
| Paul A.Frieze & Associates Ltd | Professional & scientific | 1987 |
| Paul Stallard Ltd | Professional & scientific | 2005 |
| Paulette Cohen Consulting Limited | Professional & scientific | 2022 |
| PB Mortgages Limited | Financial services | 2015 |
| Pb&Eb Rents Ltd | Real estate | 2025 |
| Pbsl Limited | Construction | 2019 |
| PD Resolve Ltd | Professional & scientific | 2026 |
| Peacheyjrsolutions Limited | Professional & scientific | 2022 |
| Pearl Cleaning World Ltd | Other services | 2023 |
| Pearl Film Services Ltd | Administrative & support | 2022 |
| Pedal Padel Ltd | Arts & recreation | 2026 |
| Pegase Airdrop Logistics International Limited | Administrative & support | 2013 |
| Pelizaro Ltd | Information & communication | 2022 |
| Pencere Ltd | Professional & scientific | 2018 |
| Pencilkit Limited | Manufacturing | 2008 |
| People First Strategy Limited | Professional & scientific | 2024 |
| People Possibilities Ltd | Other services | 2014 |
| Peoplechoice Ltd | Wholesale & retail | 2024 |
| Perfectly on PAR Limited | Wholesale & retail | 2025 |
| Perobi 42 Ltd | Arts & recreation | 2025 |
| Peter James Estates Limited | Extraterritorial | 1997 |
| Peter James Holdings Limited | Professional & scientific | 2019 |
| Petersens Localisation Limited | Administrative & support | 2011 |
| Pets TLC Ltd | Wholesale & retail | 2013 |
| PF2 Architects LLP | | 2016 |
| Pharos Limited | Professional & scientific | 1992 |
| Phenometa Limited | Information & communication | 2022 |
| Pheon X Trading Limited | Wholesale & retail | 2020 |
| Phil Eldridge Editing Limited | Information & communication | 2015 |
| Phil Irwin Carpets and Flooring Ltd | Wholesale & retail | 2019 |
| Philip & Partners Limited | Professional & scientific | 2025 |
| Philip Seidl Property Search Limited | Real estate | 2020 |
| Phoenix Subscription Marketing Consultancy Limited | Information & communication | 2018 |
| Phoenix Works Ltd | Information & communication | 2018 |
| Physio Spot Ltd | Health & social care | 2018 |
| Pinnacle Finance Limited | Information & communication | 2023 |
| Pinnacle Trade Finance Limited | Financial services | 2018 |
| Pioneer Vending Limited | Wholesale & retail | 2025 |
| Pitch-Up Pizzas Ltd | Hospitality | 2020 |
| Pivotar Ltd | Professional & scientific | 2020 |
| Pixeltide Limited | Information & communication | 2008 |
| PJ (Pyjamas) Ltd | Professional & scientific | 2019 |
| Placeapply Property Management Limited | Households | 1997 |
| Plaka Compania Naviera S.A. | | 1981 |
| Platinum Capital Developments Ltd | Real estate | 2024 |
| Playcake Ltd | Information & communication | 2015 |
| Please Kelp Productions Ltd | Information & communication | 2026 |
| Plej Limited | Real estate | 2019 |