| One Group Enterprise Ltd | Wholesale & retail | 2025 |
| One Stop Shipping Ltd | Transport & logistics | 2022 |
| Oneill Development London Ltd | Administrative & support | 2021 |
| Online Daily Deals Ltd | Wholesale & retail | 2024 |
| Only the Certified Limited | Wholesale & retail | 2024 |
| Onward Transfers Limited | Transport & logistics | 2024 |
| Onyx Motorworks Ltd | Wholesale & retail | 2025 |
| Onyxis Healthcare Ltd | Hospitality | 2023 |
| OOM Solutions Limited | Information & communication | 2020 |
| Opal Property Maintenance Ltd | Construction | 2025 |
| Oparah Limited | Health & social care | 2024 |
| OPER8 Software Ltd. | Information & communication | 2015 |
| OPER84U Ltd. | Information & communication | 2015 |
| Opine Consultants Limited | Professional & scientific | 2017 |
| OPM Securities Limited | Extraterritorial | 2008 |
| Optane Logistics Ltd | Transport & logistics | 2023 |
| Optima Engineering Limited | Professional & scientific | 2024 |
| Optimum Finish Ltd | Construction | 2022 |
| Optimus Comms Ltd | Construction | 2025 |
| Optimus Health Technologies Ltd | Information & communication | 2021 |
| ORA Glow Ltd | Wholesale & retail | 2025 |
| Orbis Computing Ltd | Wholesale & retail | 2016 |
| Orchard Bureau Ltd | Professional & scientific | 2003 |
| Organic Flow Limited | Wholesale & retail | 2025 |
| Organik Hub Limited | Wholesale & retail | 2025 |
| Organisation for Business, Innovation & Sustainability Ltd | Education | 2024 |
| Orhan Naturals Ltd | Wholesale & retail | 2026 |
| Orion TEC Services Ltd | Information & communication | 2025 |
| OSAHON3D Limited | Information & communication | 2015 |
| OSARO1 Ltd | Hospitality | 2026 |
| Osmanli Meat Ltd | Wholesale & retail | 2018 |
| Osvauto Ltd | Wholesale & retail | 2018 |
| Otimmma Care Solutions Ltd | Health & social care | 2025 |
| Otocare Essentials Ltd | Wholesale & retail | 2025 |
| Owlets Childcare Ltd. | Education | 2017 |
| Oxygne (UK) Ltd | Extraterritorial | 2015 |
| OZ Drylining Ltd | Construction | 2026 |
| Ozel Group Ltd | Construction | 2012 |
| Ozone Environmental Limited | Wholesale & retail | 2006 |
| P & FS Construction Ltd | Construction | 2025 |
| P a Care and DOM Services Limited | Administrative & support | 2022 |
| P G Sweepers Limited | Administrative & support | 2016 |
| P T London Properties Ltd | Real estate | 2020 |
| P&J Installations Limited | Construction | 2022 |
| P6 Consulting Limited | Information & communication | 2011 |
| PAA Consults Limited | Real estate | 2025 |
| Pakeeza Limited | Transport & logistics | 2020 |
| PAL Hamilton Ltd | Real estate | 2022 |
| Panda Bamboo Ltd | Hospitality | 2025 |
| Panthalassa Ltd | Education | 2022 |
| Paramount Safeguarding Ltd | Education | 2022 |
| Paramounts Properties Ltd | Real estate | 2022 |
| Parent Shield Academy Limited | Education | 2026 |
| Park Autos Ltd | Wholesale & retail | 2025 |
| Park Investments U.K. Ltd | Households | 2020 |
| Parkarounds Limited | Information & communication | 2025 |
| Parscare Limited | Health & social care | 2019 |
| Partylifemusic Ltd | Information & communication | 2022 |
| Pasha Acquisitions Limited | Real estate | 2008 |
| Pasha Brothers Group Limited | Financial services | 2018 |
| Pasha Food Products Ltd | Manufacturing | 2021 |
| Pataguu Services Ltd | Health & social care | 2025 |
| Patterson Burns Ltd | Real estate | 2024 |
| Patterson Hawke Limited | Real estate | 2006 |
| Patterson Hawthorn Ltd | Real estate | 2007 |
| Patzy Ltd | Wholesale & retail | 2025 |
| Paul Boakes Joinery Limited | Construction | 2006 |
| Pauletlocum Ltd | Health & social care | 2025 |
| Pavel Maria Ltd | Transport & logistics | 2025 |
| Pawar Blueprint Ltd | Professional & scientific | 2021 |
| Paycocke Road Limited | Real estate | 2023 |
| PB Property Maintenance Limited | Real estate | 2017 |
| Peach MK Ltd | Health & social care | 2025 |
| Peach Podiatry Ltd | Health & social care | 2019 |
| Peachy Tanning Limited | Other services | 2025 |
| Peak Services (UK) Limited | Administrative & support | 2005 |
| Peakvalue Care Services Limited | Health & social care | 2020 |
| Pealby Capital Ltd | Professional & scientific | 2023 |
| Pealby Living Limited | Administrative & support | 2022 |
| Pealby Properties Ltd | Real estate | 2020 |
| Pearlgold Limited | Real estate | 1995 |
| Penovate Limited | Other services | 2012 |
| Pentalver Sales and Conversions Limited | Professional & scientific | 2025 |
| Peoplekind Community Support & Recovery CIC | Administrative & support | 2026 |
| PEP N Peri Limited | Hospitality | 2026 |
| Perfect Decorating Limited | Construction | 2007 |
| Perfect Motors Ltd | Wholesale & retail | 2015 |
| Perfekta Ltd | Professional & scientific | 2023 |
| Perflect Ltd | Wholesale & retail | 2022 |
| Perk Initiative Ltd | Hospitality | 2021 |
| Perkz Ltd | Information & communication | 2025 |
| Perrin & Rowe Limited | Extraterritorial | 2013 |
| Perry Street (Crayford) Management Company Limited | Households | 2012 |
| Personal Care Support Ltd | Health & social care | 2019 |
| Pervezia Estates Limited | Real estate | 2025 |
| Peter Borg Limited | Administrative & support | 2016 |
| Petra Care Limited | Administrative & support | 2022 |
| Pets and Pods Studio Ltd | Manufacturing | 2019 |
| Petty Consultancy Limited | Construction | 2020 |
| PF Superior Properties Ltd | Real estate | 2021 |