| 1NTRA Ltd | Administrative & support | 2020 |
| 1NVER Limited | Administrative & support | 2024 |
| 1NVEST Limited | Professional & scientific | 2011 |
| 1NVEST Property Limited | Real estate | 2016 |
| 1NXGENTECH Holdings Limited | Financial services | 2026 |
| 1OAK Capital Limited | Financial services | 2009 |
| 1OAK Consulting Ltd | Information & communication | 2018 |
| 1OFF Media Ltd | Information & communication | 2022 |
| 1OFFICE Group Ltd | Professional & scientific | 2013 |
| 1ON1 Consultancy Ltd | Information & communication | 2014 |
| 1ONE of One Ltd | Wholesale & retail | 2024 |
| 1ONE of Oneee Limited | Wholesale & retail | 2026 |
| 1ONEBISHY Properties Limited | Real estate | 2024 |
| 1OOAK Ltd | Education | 2023 |
| 1OSD Ltd | Health & social care | 2021 |
| 1OVER11 Limited | Real estate | 2020 |
| 1OVER8 Ltd | Real estate | 2019 |
| 1P Broadband Limited | Extraterritorial | 2019 |
| 1PALLET Catering Ltd | Wholesale & retail | 2025 |
| 1PANDPC Ltd | Construction | 2024 |
| 1PB Ltd | Information & communication | 2026 |
| 1PERCENTT Ltd | Other services | 2023 |
| 1PHS Limited | Real estate | 2014 |
| 1PLANET London Ltd | Wholesale & retail | 2021 |
| 1PLANETDESIGN Limited | Professional & scientific | 2024 |
| 1PLUS Rental Ltd | Administrative & support | 2019 |
| 1PMOBILE Limited | Extraterritorial | 2016 |
| 1POINT Group Limited | Other services | 2023 |
| 1POINT21 Limited | Information & communication | 2016 |
| 1POINTMANAGEMENT Ltd | Information & communication | 2016 |
| 1PREMIER Ltd | Professional & scientific | 2023 |
| 1PUTT Ltd | Arts & recreation | 2017 |
| 1Q84 Trading Co Ltd | Manufacturing | 2023 |
| 1QG Group Limited | Information & communication | 2024 |
| 1R Group Ltd | Hospitality | 2026 |
| 1RADIOLOGY Ltd | Health & social care | 2022 |
| 1REAL Ltd | Information & communication | 2026 |
| 1REIT PLC | Real estate | 2025 |
| 1S Consulting Ltd | Information & communication | 2023 |
| 1SAIF (UK) Ltd | Information & communication | 2025 |
| 1SC Guarding Limited | Administrative & support | 1997 |
| 1SEVEN Investment Holdings Ltd | Financial services | 2022 |
| 1SEVEN Sports Management Group Ltd | Professional & scientific | 2020 |
| 1SG Limited | Real estate | 2022 |
| 1SHPB Management Company Limited | Households | 2024 |
| 1SIM Ltd | Information & communication | 2024 |
| 1SJW Management Limited | Real estate | 2007 |
| 1SMARTSTORE Ltd | Wholesale & retail | 2026 |
| 1SMILE4COMMUNITY Ltd | Health & social care | 2024 |
| 1SOVEREIGN Ltd | Administrative & support | 2008 |
| 1SRCREATIONS Limited | Information & communication | 2026 |
| 1SRLEASING Ltd | Administrative & support | 2021 |
| 1ST & Green Limited | Professional & scientific | 2021 |
| 1ST - Interactive Design Limited | Information & communication | 1996 |
| 1ST 14 Limited | Real estate | 2023 |
| 1ST 2 Clear Ltd | Water & waste | 2025 |
| 1ST 2 YOU Food Services Ltd | Hospitality | 2023 |
| 1ST 2 YOU Services Ltd | Education | 2016 |
| 1ST 4IMMIGRATION Limited | Professional & scientific | 2010 |
| 1ST Abba Limited | Education | 2020 |
| 1ST Access Training Ltd | Education | 2024 |
| 1ST Accounting Ltd | Extraterritorial | 2026 |
| 1ST Accounting Solutions Limited | Professional & scientific | 2010 |
| 1ST Ace Limited | Other services | 2024 |
| 1ST Adtube Limited | Information & communication | 2016 |
| 1ST Aesthetics Ltd | Other services | 2021 |
| 1ST AID Couriers Ltd | Transport & logistics | 2016 |
| 1ST AID Door Repair Company Limited | Professional & scientific | 1998 |
| 1ST AID Gutter Vacume Service Ltd | Administrative & support | 2026 |
| 1ST Alternative Medical Staffing Ltd | Administrative & support | 2009 |
| 1ST Alternative School Limited | Education | 2023 |
| 1ST Apostille Ltd | Other services | 2023 |
| 1ST Attempt Driving School Ltd. | Transport & logistics | 2021 |
| 1ST Blue Limited | Other services | 2025 |
| 1ST Boiler Care Ltd | Construction | 2022 |
| 1ST Born Solutions Ltd | Information & communication | 2013 |
| 1ST Born Trading Ltd | Agriculture & fishing | 2007 |
| 1ST Bridge Limited | Other services | 2026 |
| 1ST Build Limited | Other services | 2024 |
| 1ST Building Renovator Limited | Construction | 2022 |
| 1ST Business Services Ltd | Extraterritorial | 2025 |
| 1ST Call Construction Maintenance and Repair Ltd | Construction | 2025 |
| 1ST Call Group Ltd | Construction | 2019 |
| 1ST Call Home Maintenance Ltd | Construction | 2021 |
| 1ST Call Maintenance Solutions Ltd | Extraterritorial | 2013 |
| 1ST Call Plumbers Ltd | Professional & scientific | 2026 |
| 1ST Call Roofing Services Limited | Construction | 2023 |
| 1ST Call Test & Tyres Ltd | Wholesale & retail | 2021 |
| 1ST Call Tyres & Service Centre Ltd | Wholesale & retail | 2020 |
| 1ST Call Windscreens West London Limited | Wholesale & retail | 2018 |
| 1ST Capital Management Limited | Real estate | 2018 |
| 1ST Capital Partners Ltd | Professional & scientific | 2025 |
| 1ST Car Spares Limited | Wholesale & retail | 2019 |
| 1ST Care Nursing Limited | Health & social care | 2004 |
| 1ST Central Advisory Ltd | Professional & scientific | 2024 |
| 1ST Centre Limited | Other services | 2026 |
| 1ST Centre Trading Limited | Real estate | 2023 |
| 1ST Centurion Security Services Limited | Administrative & support | 2024 |
| 1ST Child Logistics Ltd | Transport & logistics | 2019 |
| 1ST Choice Accommodation Ltd | Hospitality | 2022 |