| Personal Chauffeur Ltd | Transport & logistics | 2022 |
| Personal Protective Solutions Limited | Other services | 2019 |
| Perspective Broadcast Ltd | Information & communication | 2001 |
| Pest 24 Limited | Administrative & support | 2024 |
| Pet Professionals (Franchising) Limited | Education | 2012 |
| Pet Shed Limited | Wholesale & retail | 2003 |
| Pete's Micro Bakery Ltd | Manufacturing | 2024 |
| Peter Cramp Limited | Wholesale & retail | 2024 |
| Peter Finlayson Associates Ltd. | Professional & scientific | 2002 |
| Peter Howard Limited | Wholesale & retail | 1944 |
| Peter Maksymuk Surveying Limited | Administrative & support | 2010 |
| Peter Richard Property Limited | Real estate | 2025 |
| Peter's Butchery Limited | Hospitality | 2022 |
| Peters Supply and Transport Ltd | Wholesale & retail | 2026 |
| Petishal Limited | Real estate | 2025 |
| Petroil Engineering Limited | Manufacturing | 1994 |
| Pets' Kitchen Limited | Manufacturing | 2005 |
| Pewex Logistic Ltd | Transport & logistics | 2019 |
| Pewsey Wharf Boat Club | Other services | 2003 |
| Pewsham Curtis Ltd | Wholesale & retail | 2026 |
| PFA Consulting EOT Limited | Administrative & support | 2022 |
| PFA Consulting Holdings Ltd | Professional & scientific | 2019 |
| PFA Consulting Ltd | Professional & scientific | 1999 |
| PFA Ltd | Professional & scientific | 2008 |
| Pfasys Ltd | Water & waste | 2025 |
| PFD Decorating Ltd | Construction | 2020 |
| PGG Limited | Construction | 2022 |
| PHA Invest Ltd | Real estate | 2023 |
| Phai Services Limited | Information & communication | 2016 |
| Pharm.Jlee Ltd | Health & social care | 2018 |
| Pharmeng Solutions Ltd | Professional & scientific | 2025 |
| Phase & Create Limited | Professional & scientific | 2022 |
| Phaze One Swindon Limited | Other services | 2026 |
| PHC Clinics Ltd | Health & social care | 2023 |
| Phiertechnologies Ltd | Information & communication | 2020 |
| Phil Deacon Consulting Ltd | Financial services | 2025 |
| Phil White Quantity Surveyor Ltd | Construction | 2016 |
| Philadelphia Court RTM Company Limited | Households | 2023 |
| Philbay Investments Private Limited | Health & social care | 2013 |
| Phillips & Sheldon Ltd | Administrative & support | 2023 |
| Phillips and Laken Limited | Construction | 2009 |
| Phillips and Sutton Limited | Construction | 1994 |
| Philmack Limited | Administrative & support | 2016 |
| Phinos Company Limited | Health & social care | 2020 |
| Phoenix Electrical Services (Swindon) Limited | Construction | 2001 |
| Phoenix Enterprises (Swindon) Ltd | Administrative & support | 2002 |
| Phoenix Extensions Limited | Construction | 2009 |
| Phoenix Heritage Motor Engineering CIC | Wholesale & retail | 2021 |
| Phoenix Home and Heating Ltd | Construction | 2022 |
| Phoenix Home Lettings Ltd | Real estate | 2024 |
| Phone Accessories Ltd | Wholesale & retail | 2018 |
| Phone Tech GL1 Ltd | Other services | 2022 |
| Phonefixers Limited | Information & communication | 2015 |
| Phonepimps Limited | Wholesale & retail | 2013 |
| Photonforge Group Ltd | Manufacturing | 2025 |
| Phtwc Limited | Real estate | 2019 |
| Phyllis Uhuru Ltd | Health & social care | 2019 |
| Phyner Ltd | Information & communication | 2020 |
| Physiorx Ltd | Education | 2021 |
| PI Business Development Limited | Extraterritorial | 2001 |
| PI of Things Limited | Information & communication | 2022 |
| PI Projects Analytical Ltd | Professional & scientific | 2025 |
| Pi$O Ltd | Transport & logistics | 2021 |
| Piazza Holdco 1 Ltd | Energy | 2023 |
| Piazza Holdco 2 Ltd | Energy | 2023 |
| Picadrew Productions Limited | Manufacturing | 2025 |
| Pick a Ticket Ltd | Other services | 2024 |
| Pickering Business Services Limited | Administrative & support | 2011 |
| Pico Limited | Real estate | 2023 |
| Picturelizard Limited | Professional & scientific | 2006 |
| Pierre Oliveira - Mentor DE Negócios Ltd | Professional & scientific | 2024 |
| PIG Nose Technology Ltd | Information & communication | 2025 |
| Pilgrim Close (Swindon) Management Company Limited | Real estate | 2020 |
| Pillar-X Freehold Limited | Real estate | 2021 |
| Pillar-X Limited | Real estate | 2020 |
| Pillar-X SA Limited | Hospitality | 2023 |
| Pine & Oak Residential Homes Ltd | Health & social care | 2023 |
| PINEAPPLEQT81 Ltd | Hospitality | 2021 |
| Pinewood School Limited | Education | 1938 |
| Pini’S Dance Academy Ltd | Education | 2025 |
| Pink Care Ltd | Health & social care | 2025 |
| Pink Cat Crafts & Charms Ltd | Wholesale & retail | 2022 |
| Pink Volt Records Ltd | Information & communication | 2024 |
| Pinky's DS Services Ltd | Wholesale & retail | 2024 |
| Pinnacle (Old Town) Management Limited | Households | 2001 |
| Pinp Ltd | Manufacturing | 2026 |
| Pinpoint Creative Limited | Professional & scientific | 2013 |
| Pinto Pereira Ltd | Health & social care | 2017 |
| Pioneer Consultancy Services UK Limited | Information & communication | 2009 |
| Pioneer Labour Services Limited | Construction | 2008 |
| Pioneer Motorcar Restorations Limited | Wholesale & retail | 2025 |
| Piotr Boguta LPH Ltd | Health & social care | 2023 |
| Piper Javelin Holding Company Limited | Financial services | 2017 |
| Piper Javelin NO 1 Limited | Construction | 2017 |
| Piplag Brothers Limited | Hospitality | 2024 |
| Pippin Bakers Ltd | Manufacturing | 2014 |
| Piranha Parcels Limited | Transport & logistics | 2020 |
| Pires & Co. Limited | Extraterritorial | 2024 |
| Pisces Aroma Limited | Hospitality | 2011 |
| Pishon Investments Ltd | Real estate | 2025 |