| IB Commercial Cleaning Ltd | Administrative & support | 2022 |
| IB Residential Cleaning Limited | Administrative & support | 2025 |
| Ibunos Limited | Wholesale & retail | 2023 |
| Icad.Designsolutions Limited | Professional & scientific | 2016 |
| Icapture Productionz Limited | Arts & recreation | 2008 |
| ICL Projects Solutions Limited | Real estate | 2013 |
| Icnl London Ltd | Information & communication | 2013 |
| ICO Properties Limited | Real estate | 2023 |
| Iconic Barbers Ltd | Other services | 2017 |
| Iconic Beauty and Aesthetics Clinic Ltd | Health & social care | 2023 |
| ICT Books Ltd | Professional & scientific | 2026 |
| ID Spencer Ltd | Wholesale & retail | 2019 |
| Idaisy UK Limited | Administrative & support | 2016 |
| Idbl Limited | Wholesale & retail | 2021 |
| Idea-Hub UK Ltd | Information & communication | 2023 |
| Ideal Building Ltd | Construction | 2019 |
| Ideavaz Ltd | Transport & logistics | 2018 |
| IDG Cleaning Limited | Administrative & support | 2025 |
| IDG Properties Limited | Financial services | 2026 |
| IDH Alarms Company Limited | Construction | 1981 |
| IDS Compliance Ltd | Transport & logistics | 2021 |
| IF YOU Review Ltd | Wholesale & retail | 2024 |
| Iflcleaning Ltd | Professional & scientific | 2015 |
| IFM Contractors Limited | Construction | 2024 |
| Ifmoop Limited | Health & social care | 2014 |
| Iftekhar Consulting Limited | Professional & scientific | 2026 |
| Iftikutz Ltd | Other services | 2021 |
| Ifybaby Limited | Health & social care | 2021 |
| IGR Solutions Ltd | Construction | 2026 |
| IJ Property Services Ltd | Households | 2026 |
| IJN Studios Ltd | Professional & scientific | 2023 |
| IKE Property Services Limited | Real estate | 2026 |
| Ikegift Construction Limited | Construction | 2021 |
| Ikon Nightlife Ltd | Hospitality | 2025 |
| Ikon Protection Ltd | Administrative & support | 2021 |
| IL Padrino Ltd | Hospitality | 2025 |
| Ilie Fana Ltd | Construction | 2024 |
| ILJ Property Solutions Limited | Construction | 2022 |
| Ilker Gravesend Ltd | Other services | 2015 |
| Illyrian Build & Solutions Ltd | Construction | 2025 |
| IMAGE4BUSINESS Limited | Information & communication | 2008 |
| Imaluck Care Ltd | Health & social care | 2022 |
| Imco Building Services Ltd | Construction | 2014 |
| Imet Solution Ltd | Other services | 2022 |
| IMM Construction&Cleaning Limited | Construction | 2020 |
| Immortality Consult Limited | Professional & scientific | 2012 |
| Impart Graphics Ltd | Information & communication | 2013 |
| Imperial Fire Consultants Limited | Professional & scientific | 2024 |
| Imunch Ltd | Administrative & support | 2014 |
| IMW Commercial Ltd | Other services | 2019 |
| IN Jointing & Cable Installation Ltd | Construction | 2025 |
| IN Nome DEL Padre Ltd | Hospitality | 2026 |
| IN Sync Generators Ltd | Manufacturing | 2023 |
| Inclusive Social Care Limited | Health & social care | 2023 |
| Inclusive Working Ltd | Education | 2021 |
| Independent Commissioning Engineering Ltd | Manufacturing | 2024 |
| Indian Grocery Store Ltd | Wholesale & retail | 2024 |
| Indian Lounge Spice Ltd | Hospitality | 2025 |
| Indian Valley Limited | Hospitality | 2020 |
| Indie Shooters Limited | Information & communication | 2025 |
| Indigo Bridge Limited | Construction | 2023 |
| Indipave Ltd | Construction | 2017 |
| Indo-Global Polymers Ltd | Wholesale & retail | 2025 |
| Indulge Infusions Ltd | Manufacturing | 2021 |
| Industrial Instrument Services Ltd | Administrative & support | 1997 |
| Indy Logistics Ltd | Transport & logistics | 2025 |
| Ineffable Films Ltd | Manufacturing | 2018 |
| Inferno Box Ltd | Hospitality | 2023 |
| Infinite Ascent Ventures Ltd | Information & communication | 2025 |
| Infinite Haulage Ltd | Wholesale & retail | 2026 |
| Infinite Rope Access Ltd | Construction | 2014 |
| Infinity Holidays Ltd | Other services | 2022 |
| INFINITY68 Limited | Health & social care | 2013 |
| Infomax Projects Ltd | Real estate | 2013 |
| Inform Architectural Services Limited | Professional & scientific | 2009 |
| Information Technology World Wide Limited | Professional & scientific | 2008 |
| Infraren Ltd | Transport & logistics | 2022 |
| Initial Response Events Limited | Health & social care | 2025 |
| Inizio Properties Limited | Real estate | 2020 |
| Inkaje Ltd | Wholesale & retail | 2024 |
| Inksquad Ltd | Wholesale & retail | 2015 |
| Inkstinctive Designs Ltd | Professional & scientific | 2023 |
| Inmatic Ltd | Wholesale & retail | 2020 |
| Innercity House Management Limited | Households | 1999 |
| Innosen Interior Finisher Ltd | Construction | 2025 |
| Innovate Consultants Limited | Professional & scientific | 2016 |
| Innovative Resources Limited | Agriculture & fishing | 2002 |
| INOV8 Homes Ltd | Construction | 2002 |
| Inparty Limited | Other services | 2016 |
| Inside OUT Security Ltd | Professional & scientific | 2026 |
| Insight Asset Management Ltd | Real estate | 2019 |
| Insight Capacity Experts Ltd | Health & social care | 2024 |
| Insight Edge Coaching & Consultancy Ltd | Professional & scientific | 2023 |
| Insight OS Limited | Information & communication | 2026 |
| Insight Psychology Ltd | Health & social care | 2012 |
| Insite IT Systems Limited | Information & communication | 2012 |
| Insourcing Solutions Ltd | Health & social care | 2023 |
| Inspire Ventilation Limited | Construction | 2020 |
| Inspired Property Services (SE) Limited | Construction | 2022 |
| Inspired Tongue Music Limited | Information & communication | 2022 |