| OQP Services Limited | Construction | 2021 |
| Orange Crop Ltd | Real estate | 2024 |
| Orange Grove Limited | Wholesale & retail | 2012 |
| Orange Hexagon Consulting Limited | Professional & scientific | 2019 |
| Orangutan Productions Limited | Arts & recreation | 2012 |
| Orchard Meadow Therapies Limited | Other services | 2012 |
| Orchard Road Freehold Limited | Households | 1992 |
| Organic Goodness Ltd | Wholesale & retail | 2019 |
| Organized Workshop and Facilities Management Ltd | Administrative & support | 2018 |
| Oria Studio Ltd | Wholesale & retail | 2026 |
| Oriel Court Management Company Limited | Professional & scientific | 2003 |
| Original Wisdom Ltd | Education | 2019 |
| Orion Global Consulting OGC Ltd | Professional & scientific | 2024 |
| Orion Global Solutions Limited | Professional & scientific | 2024 |
| Orivyn Limited | Information & communication | 2023 |
| Orleans Cakes Limited | Wholesale & retail | 2025 |
| Orleans Garage Ltd | Wholesale & retail | 2022 |
| Orleans Park School | Education | 2012 |
| Osarumwse Services Limited | Health & social care | 2022 |
| OSF Holdings Ltd | Administrative & support | 2021 |
| Osteopathy Care Limited | Health & social care | 2025 |
| OTF Ltd | Transport & logistics | 2010 |
| Otteo Limited | Extraterritorial | 2023 |
| OUR Lady Valentine Ltd | Arts & recreation | 2018 |
| Outside the Box Lettings Ltd | Households | 2019 |
| Outsider Communications Ltd | Professional & scientific | 2022 |
| Overgrowth Media Ltd | Information & communication | 2023 |
| Ovyiuliu Limited | Transport & logistics | 2021 |
| Owrg Limited | Information & communication | 2013 |
| Oxborrow and Henderson Limited | Health & social care | 2018 |
| Oxygen Resourcing Ltd | Administrative & support | 2025 |
| Oxypod Ltd | Health & social care | 2021 |
| Oyada Design Ltd | Wholesale & retail | 2018 |
| Oyster Library Ltd | Wholesale & retail | 2021 |
| O’Rourke Bespoke Ltd | Construction | 2024 |
| P & a Imaging Limited | Wholesale & retail | 2016 |
| P & M UK Associates Ltd | Hospitality | 2022 |
| P Mercy & Co Limited | Administrative & support | 2014 |
| P S Ceramics Limited | Construction | 2019 |
| P Wojton Ltd | Construction | 2016 |
| P&B London Properties Limited | Real estate | 2024 |
| P&F Housing Development Ltd | Construction | 2023 |
| P&W Enterprises Limited | Real estate | 2025 |
| P-Leigh Lodge Ltd | Households | 2024 |
| P.A. Molloy Builders Limited | Construction | 2012 |
| P.I.C Style Ltd | Wholesale & retail | 2015 |
| P3 Technology Ltd | Information & communication | 2003 |
| P3J Estates Ltd | Real estate | 2019 |
| Pachra Limited | Wholesale & retail | 2025 |
| Padda Brothers Limited | Real estate | 2023 |
| Padelero CIC | Education | 2025 |
| Paedgastro Consults Limited | Health & social care | 2017 |
| Page & Sandys Properties Ltd | Real estate | 2021 |
| Pakcha Studio Ltd | Information & communication | 2023 |
| Palatinate Studios LLP | | 2015 |
| Pall Mall Thoroughbreds Ltd | Arts & recreation | 2025 |
| Palmer Management Services Limited | Professional & scientific | 2025 |
| Panayis Ltd | Hospitality | 2018 |
| Panda Rouge Ltd | Manufacturing | 2012 |
| Panelands Limited | Real estate | 1979 |
| Panjean Limited | Health & social care | 2021 |
| Panther Works Ltd | Wholesale & retail | 2020 |
| Papers & Booze Ltd | Information & communication | 2022 |
| Paragon Enquiry Services Limited | Information & communication | 2021 |
| Paragon Investment Management Limited | Financial services | 2005 |
| Parakeet Services Ltd | Information & communication | 2010 |
| Paramount Healthcare Services Limited | Health & social care | 2020 |
| Paramount Legal Services Ltd | Professional & scientific | 2024 |
| Paredes Plumbing Ltd | Construction | 2022 |
| Parga Advisory Ltd | Professional & scientific | 2025 |
| Park Court (Hounslow) Management Company Limited | Households | 1995 |
| Park Road (Beresford Court) Management Limited | Households | 1971 |
| Park Road (Twickenham) RTM Company Limited | Real estate | 2022 |
| Parkfield Construction Ltd | Construction | 2024 |
| Parkhouse Media Limited | Information & communication | 2014 |
| Parklands Consulting Limited | Professional & scientific | 2013 |
| Parkway Greens Richmond Ltd | Wholesale & retail | 2025 |
| Parsons Advisory Services Ltd | Professional & scientific | 2022 |
| Parsons Sports Rehab Limited | Health & social care | 2019 |
| Part Plastik Holdings Ltd | Real estate | 2019 |
| Part Plastik Ltd | Real estate | 2018 |
| Passacaglia Limited | Information & communication | 2014 |
| Passport to Leisure Limited | Arts & recreation | 2001 |
| Pastiamo Limited | Manufacturing | 2017 |
| Path Partners Limited | Professional & scientific | 2024 |
| Path to Impact Ltd | Professional & scientific | 2023 |
| Patlix Ltd | Information & communication | 2025 |
| Paul Buckmaster Creative Ltd | Information & communication | 2025 |
| Paul Feven Limited | Professional & scientific | 2013 |
| Pauljones.Tv Ltd | Information & communication | 2011 |
| Pavo Indus Ltd | Real estate | 2022 |
| Pawfect Pups Ltd | Manufacturing | 2023 |
| Paxton & Pexton Ltd | Professional & scientific | 2022 |
| Pay-Your-Way Ltd | Information & communication | 2016 |
| Payne Domestic Services Ltd | Administrative & support | 2023 |
| PB Hosts Ltd | Information & communication | 2021 |
| PBR Properties Limited | Real estate | 2003 |
| PC Fast Solutions Limited | Construction | 2025 |
| PC Gabriel Ltd | Manufacturing | 2025 |
| PCD Event Consulting Ltd | Professional & scientific | 2019 |