| Ibetech Ltd | Information & communication | 2018 |
| Ibis Investment Property Ltd | Real estate | 2021 |
| Ibiza Designs Limited | Construction | 2018 |
| Ibridge Finance Limited | Administrative & support | 2011 |
| IBS Technologies Limited | Information & communication | 2024 |
| Ibuildng (UK) Ltd | Construction | 2013 |
| Ice Helicopters Limited | Administrative & support | 2019 |
| Icon Framers Ltd | Manufacturing | 2008 |
| ID Real Estate Ltd | Real estate | 2025 |
| Ideal Accident Claims Management Limited | Professional & scientific | 2009 |
| Ideas Realised Ltd | Construction | 2019 |
| Idee IT Ltd | Information & communication | 2022 |
| Identas Productions Ltd | Arts & recreation | 2024 |
| Identity Experts Limited | Information & communication | 2014 |
| IDI Operatives Ltd | Construction | 2019 |
| Idipc LLP | | 2012 |
| Idream Holdings Ltd | Financial services | 2021 |
| IDU Enterprise Limited | Professional & scientific | 2011 |
| IDU Interiors Ltd | Construction | 2012 |
| IDU Properties Ltd | Real estate | 2023 |
| Iebg Limited | Professional & scientific | 2018 |
| Iecoklean Limited | Other services | 2012 |
| IF2 Limited | Construction | 2010 |
| Ifdc Properties Limited | Real estate | 1999 |
| Ifedimma Wellness Ltd | Administrative & support | 2022 |
| IGP Engineering Ltd | Manufacturing | 2011 |
| Igtechno Limited | Wholesale & retail | 2015 |
| Iguana Energy Group Limited | Other services | 2019 |
| IHL Builders Ltd | Construction | 2021 |
| Ihomes (Enfield) Ltd | Real estate | 2019 |
| Ihomes (Hendon) Ltd | Real estate | 2021 |
| Ihomes (London) Limited | Construction | 2007 |
| IIP (2004) Limited | Real estate | 2006 |
| IJ Medicare Ltd | Health & social care | 2022 |
| IJA Homes Limited | Real estate | 2025 |
| IJH Electrical Services Ltd | Construction | 2022 |
| Ikon Services Limited | Health & social care | 1997 |
| ILK Entertainment Limited | Arts & recreation | 2020 |
| Illuminated Films (Christmas Carol) Limited | Arts & recreation | 1995 |
| Illuminated Films (Little Princess) Ltd | Information & communication | 2017 |
| Illuminated Films (Rocket) Limited | Information & communication | 2019 |
| Illuminated Films (WAR Game) Limited | Information & communication | 2001 |
| Illuminated Productions Limited | Information & communication | 2000 |
| IM Racing Ltd | Arts & recreation | 2017 |
| IMA Gold Ltd | Professional & scientific | 2026 |
| Imeus Limited | Health & social care | 2015 |
| Immeri Ltd | Wholesale & retail | 2023 |
| Impact Data Solutions Limited | Construction | 2009 |
| Impact Film Studios Limited | Information & communication | 2026 |
| Impact Global Ltd | Real estate | 2022 |
| Impactchoice Limited | Administrative & support | 2009 |
| Imperial Development Management Ltd | Construction | 2012 |
| Imperial Ecdb Manorgate Limited | Construction | 2019 |
| Imperial Penthouse Ltd | Construction | 2015 |
| Imperial Penthouse Mattock Lane Limited | Construction | 2018 |
| Imperial Performance Network Ltd | Health & social care | 2023 |
| Imperium Capital Estates Limited | Real estate | 2017 |
| Imperium Electrical & Security Solutions Ltd | Construction | 2021 |
| Imperium Properties (London) Limited | Real estate | 2022 |
| Impex Fashion Accessories Limited | Wholesale & retail | 1998 |
| Implant Success Limited | Other services | 2022 |
| Impression Properties Limited | Other services | 2004 |
| Impulse Entertainment Limited | Arts & recreation | 2014 |
| Imran UK Traders Ltd | Wholesale & retail | 2026 |
| IMS Fixers Ltd | Construction | 2017 |
| Ims&M Technology Ltd | Manufacturing | 2012 |
| Imyach Limited | Real estate | 2017 |
| IN Home Care Chichester Limited | Health & social care | 2017 |
| IN Home Care Grayshott Limited | Health & social care | 2017 |
| IN Home Care Limited | Health & social care | 2011 |
| IN Home Care Management Limited | Health & social care | 2017 |
| IN Search of Sun Ltd | Information & communication | 2021 |
| Inca Developments Limited | Construction | 2012 |
| Independent Creative Academy Ltd | Education | 2022 |
| Independent Creative Casting Ltd | Administrative & support | 2022 |
| Independent Creative Group Ltd | Arts & recreation | 2022 |
| Independent Creative Management Ltd | Professional & scientific | 2021 |
| Independent Creative PR Limited | Professional & scientific | 2023 |
| Independent Creative Productions Ltd | Information & communication | 2024 |
| Independent Creative Sports Ltd | Professional & scientific | 2024 |
| Independent Media News Limited | Information & communication | 2002 |
| Indian Doll’S House Film Ltd | Information & communication | 2019 |
| Indian Stories 2 Limited | Information & communication | 2024 |
| Indian Stories Limited | Information & communication | 2024 |
| Indre Chever Interiors Limited | Professional & scientific | 2020 |
| Indujay Properties Ltd | Real estate | 2024 |
| Indulge Travel Limited | Administrative & support | 2023 |
| Indulgence Chauffeurs Ltd | Transport & logistics | 2025 |
| Industrious Energy Limited | Information & communication | 2019 |
| Infenso Limited | Information & communication | 2017 |
| Inference Ltd | Information & communication | 2021 |
| Infiled EM International Ltd | Manufacturing | 2016 |
| Infinia Limited | Information & communication | 2022 |
| Infinity Airways Ltd | Transport & logistics | 2023 |
| Infinity Clinic Services Ltd | Health & social care | 2023 |
| Infinity EYE Services Limited | Health & social care | 2016 |
| Infinity Self Storage Holdings Limited | Real estate | 2019 |
| Infinity Store and Work Limited | Real estate | 2024 |
| Infiniun Ltd | Information & communication | 2025 |
| Infire Safety Systems Ltd | Administrative & support | 2020 |