| Inside Connections Limited | Information & communication | 2016 |
| Inside Connections Living Limited | Hospitality | 2017 |
| Inside Connections Mobile Limited | Information & communication | 2019 |
| Inside Connections Recruitment Limited | Administrative & support | 2019 |
| Inside Connections Support CIC | Administrative & support | 2017 |
| Inside Connections Training Limited | Education | 2017 |
| Inside OUT Property Services Ltd | Administrative & support | 2024 |
| Insight Decorators Ltd | Other services | 2016 |
| Insight Diagnostics Global Limited | Real estate | 2024 |
| Insight QA Ltd | Professional & scientific | 2023 |
| Insight Retailing Ltd | Wholesale & retail | 2017 |
| INSIGHT2DRIVE Ltd | Education | 2007 |
| Insightful Industries Ltd | Information & communication | 2023 |
| Insightful Innovation Limited | Information & communication | 2020 |
| Insightia Property Acquisitions Limited | Real estate | 2025 |
| Insmec Ltd | Professional & scientific | 2011 |
| Inspection & Power Services Ltd | Professional & scientific | 2024 |
| Inspira Health Care Ltd | Public administration | 2023 |
| Inspire Consultants Ltd | Wholesale & retail | 2022 |
| Inspire Customer Contact Partnership Ltd | Professional & scientific | 2019 |
| Inspire HR Consultancy Ltd | Administrative & support | 2016 |
| Inspire Landscaping and Paving Specialists Ltd | Administrative & support | 2018 |
| Inspire Merseyside CIC | Education | 2022 |
| Inspire Rail Ltd | Professional & scientific | 2014 |
| Inspire Signature Group Limited | Financial services | 2021 |
| Inspire Software Solutions Ltd | Information & communication | 2012 |
| Inspired Nutrition 3 Ltd | Health & social care | 2022 |
| Inspired 2 Care Limited | Health & social care | 2019 |
| Inspired by Life Ltd | Health & social care | 2021 |
| Inspired Images Limited | Professional & scientific | 2025 |
| Inspired Pablos Ltd | Financial services | 2020 |
| Inspired Pilates Ltd | Other services | 2025 |
| Inspired Telecoms Contracting Services Limited | Information & communication | 2025 |
| Inspiring Pathways Limited | Administrative & support | 2022 |
| Inspiring Through Sports CIC | Education | 2024 |
| Insspire Studio Ltd | Professional & scientific | 2009 |
| Insta Plumbing and Heating Services Ltd | Construction | 2022 |
| Instant Blooms Ltd | Wholesale & retail | 2026 |
| Instant Online Conveyancing Quote Limited | Information & communication | 2021 |
| Instant Title Solutions Limited | Information & communication | 2019 |
| Institute of Employment Rights | Information & communication | 1989 |
| Institute of Training and Occupational Learning Limited | Other services | 2009 |
| Instruct Lettings Ltd | Real estate | 2023 |
| Instruxo Limited | Information & communication | 2024 |
| Instyle Property Limited | Real estate | 2012 |
| Insulation Installers Ltd | Construction | 2022 |
| Insurehub Ltd | Financial services | 2025 |
| Intabene Limited | Professional & scientific | 2021 |
| Intacase Ltd | Wholesale & retail | 2021 |
| Intact Roofing Limited | Construction | 2023 |
| Intaglobe Schoolwear Limited | Wholesale & retail | 2005 |
| Intech Print Services Ltd | Professional & scientific | 2015 |
| Integ Academy Ltd | Education | 2024 |
| Integra Health and Wellbeing Limited | Education | 2013 |
| Integra Security Systems Limited | Administrative & support | 2004 |
| Integral Experts Ltd | Professional & scientific | 2024 |
| Integral Facilities Ltd | Administrative & support | 2025 |
| Integral Productions Limited | Information & communication | 2002 |
| Integral Properties North West Limited | Real estate | 2014 |
| Integrate Developments Limited | Real estate | 2006 |
| Integrate FM Ltd | Administrative & support | 2009 |
| Integrate Law Limited | Professional & scientific | 2023 |
| Integrated and Collaborative Design and Planning Ltd | Construction | 2023 |
| Integrated Communities Security Ltd | Financial services | 2025 |
| Integrated Estates Management Ltd | Administrative & support | 2018 |
| Integrated Network Hardware Ltd. | Information & communication | 2016 |
| Integrated Oilfield Associates Limited | Other services | 2011 |
| Integrated Parking Ltd | Administrative & support | 2014 |
| Integrated Radiological Services (IRS) Limited | Professional & scientific | 1985 |
| Integrated Waterflood Management Limited | Mining & quarrying | 2018 |
| Integrateproperty Ltd | Construction | 2025 |
| Integrio Ltd | Health & social care | 2026 |
| Integritas Property Construction Ltd | Construction | 2025 |
| Integritas Property Group (IPG) Holdings Ltd | Real estate | 2024 |
| Integritas Property Group (IPG) Limited | Construction | 2021 |
| Integritas Property Group (IPG) Number 10 Ltd | Construction | 2023 |
| Integritas Property Group (IPG) Number 11 Ltd | Construction | 2024 |
| Integritas Property Group (IPG) Number 12 Ltd | Construction | 2024 |
| Integritas Property Group (IPG) Number 14 Ltd | Construction | 2025 |
| Integritas Property Group (IPG) Number 3 Ltd | Real estate | 2021 |
| Integritas Property Group (IPG) Number 4 Ltd | Real estate | 2021 |
| Integritas Property Group (IPG) Number 5 Ltd | Construction | 2021 |
| Integritas Property Group (IPG) Number 6 Ltd | Real estate | 2022 |
| Integritas Property Group (IPG) Number 7 Ltd | Construction | 2022 |
| Integritas Property Group (IPG) Number 8 Ltd | Construction | 2023 |
| Integritas Property Group (IPG) Number 9 Ltd | Construction | 2023 |
| Integrity Boxing Management Ltd | Arts & recreation | 2025 |
| Integrity Building Construction Ltd | Construction | 2026 |
| Integrity Estates Limited | Construction | 2019 |
| Integrity Fire Protection Ltd | Public administration | 2023 |
| Integrity Property Consultants Limited | Administrative & support | 2017 |
| Integrum (NW) Ltd | Construction | 2021 |
| Intek Fire & Safety Solutions Ltd | Other services | 2022 |
| Intellbuild Ltd | Construction | 2018 |
| Intellect Power Square UK Limited | Real estate | 2021 |
| Intellectra Tech Ltd | Information & communication | 2024 |
| Intellegri Ltd | Information & communication | 2022 |
| Intellevent Ltd | Administrative & support | 2021 |
| Intellica Group Limited | Professional & scientific | 2017 |
| Intellica Limited | Professional & scientific | 2014 |