| Infinity UK Developments Ltd | Real estate | 2016 |
| Infinity UK Investments Ltd | Hospitality | 2022 |
| Infinity Wall Art Ltd | Wholesale & retail | 2012 |
| Infinity Warehousing & Logistics Ltd | Transport & logistics | 2022 |
| Infinity-Fashion-Uk Limited | Wholesale & retail | 2025 |
| INFINITYKITCHEN44 Ltd | Hospitality | 2024 |
| Inflatable Feasts & Consultancy Services Ltd | Hospitality | 2024 |
| Infloheat Limited | Construction | 2019 |
| Inflori Enterprises UK Ltd | Wholesale & retail | 2021 |
| Influx Connect Ltd | Professional & scientific | 2025 |
| Infocus Media Production Limited | Information & communication | 2018 |
| Infodmz Limited | Information & communication | 2018 |
| Infolinx Ltd | Information & communication | 2025 |
| Infonet Systems Ltd | Information & communication | 2024 |
| Infonite Limited | Administrative & support | 2008 |
| Infonomic Limited | Professional & scientific | 2003 |
| Inform Housing Services Ltd | Real estate | 2025 |
| Inform Metrics Consulting Ltd | Information & communication | 2023 |
| Informed Genomics Limited | Professional & scientific | 2020 |
| Inforox Limited | Information & communication | 2012 |
| Infotechnosys Limited | Information & communication | 2020 |
| Infotek Consulting Limited | Information & communication | 2024 |
| Infotenix Ltd | Information & communication | 2022 |
| Infra Consultancy Limited | Professional & scientific | 2008 |
| Infra Skills Ltd | Professional & scientific | 2013 |
| Inframeaxis Ltd | Wholesale & retail | 2026 |
| Infrared Solutions Limited | Construction | 2026 |
| Infrastructure Delivery Services Limited | Construction | 2017 |
| Infratech Hardware Limited | Professional & scientific | 2015 |
| Infrava Group Limited | Information & communication | 2026 |
| Infrism Technologies Ltd | Information & communication | 2018 |
| Infuse IT Limited | Wholesale & retail | 2025 |
| Infuse Property Ltd | Financial services | 2018 |
| Infuseyou Limited | Other services | 2025 |
| ING Tutoring Ltd | Education | 2024 |
| Ingenics Management Consulting Limited | Professional & scientific | 2020 |
| Inginium Limited | Professional & scientific | 2026 |
| Inginium Properties Limited | Real estate | 2024 |
| Ingleby (1699) Limited | Administrative & support | 2006 |
| Ingleby (1799) Limited | Administrative & support | 2008 |
| Ingleby Holdings Limited | Professional & scientific | 1936 |
| Ingleby Nominees Limited | Professional & scientific | 1984 |
| Inglehope Services Limited | Construction | 2015 |
| Inglewood Holdings Limited | Real estate | 2025 |
| Ingo Professionals CIC | Health & social care | 2025 |
| Ingot Studios Limited | Arts & recreation | 2014 |
| Ingram Security and Electrical Limited | Administrative & support | 2012 |
| Ingrid Just Unique Ltd | Other services | 2025 |
| INH Property Repairs Ltd | Construction | 2008 |
| Inherit Asset Solutions Ltd | Financial services | 2018 |
| Inhome Commercial and Sales Ltd | Real estate | 2017 |
| Inhome Estates Limited | Real estate | 2013 |
| INI Transport Limited | Transport & logistics | 2022 |
| Inicio Tech Ltd | Information & communication | 2017 |
| Iniesta Natural Skin Care Ltd | Other services | 2025 |
| Inigo Business Centres Limited | Administrative & support | 1997 |
| Inir Ltd | Hospitality | 2020 |
| Inish Limited | Health & social care | 2020 |
| Initbit Technologies UK Ltd | Information & communication | 2013 |
| Inite Limited | Wholesale & retail | 2016 |
| Initial Asset Management Limited | Real estate | 2026 |
| Initial Builder Limited | Construction | 2023 |
| Initial Parking Holdings Limited | Professional & scientific | 2026 |
| Initial Parking Limited | Other services | 2019 |
| Initiative for Social Entrepreneurs C.I.C. | Professional & scientific | 2000 |
| Initium Housing Ltd | Health & social care | 2025 |
| Inix Studios Ltd | Information & communication | 2025 |
| Injury 4 U Ltd | Administrative & support | 2018 |
| INK & North Limited | Professional & scientific | 2025 |
| INK & Panel Ltd | Information & communication | 2025 |
| INK and Lens Ltd | Information & communication | 2025 |
| INK Tree Ltd | Information & communication | 2024 |
| Inkaya Electrics Ltd | Administrative & support | 2018 |
| Inkedup Ltd | Arts & recreation | 2015 |
| Inken Limited | Wholesale & retail | 2025 |
| Inkerman Leisure Limited | Education | 2004 |
| Inkerman Properties Limited | Construction | 2002 |
| Inkforever Ltd | Wholesale & retail | 2026 |
| Inkosi Ltd | Health & social care | 2007 |
| Inks R US Ltd | Wholesale & retail | 2019 |
| Inkudy Studio Ltd | Wholesale & retail | 2026 |
| Inkybear Games Limited | Manufacturing | 2020 |
| Inland ZDP PLC | Financial services | 2012 |
| Inlet GAS Services Ltd | Construction | 2002 |
| Inlico Limited | Wholesale & retail | 2000 |
| Inlux Robotics Ltd | Wholesale & retail | 2026 |
| Inmemory Consultancy Limited | Information & communication | 2012 |
| Inn Care Housing Ltd | Hospitality | 2021 |
| Inn Housing Ltd | Real estate | 2023 |
| Innalytx for Consulting and Smart Solutions Limited | Information & communication | 2025 |
| Innate Bodhi Ltd | Extraterritorial | 2014 |
| Innate Limited | Extraterritorial | 2000 |
| Innate Management Systems Limited | Information & communication | 1992 |
| Innate Systems Limited | Information & communication | 1997 |
| Inncreate Ltd | Professional & scientific | 2024 |
| Inndependent Hotels Ltd | Hospitality | 2021 |
| Inner Circle Catering & Events Ltd | Hospitality | 2025 |
| Inner Circle Recovery Limited | Wholesale & retail | 2020 |
| Inner City Champs Assoc. C.I.C. | Arts & recreation | 2014 |
| Inner City Childcare Ltd | Education | 2021 |