| HTP Investments Limited | Wholesale & retail | 2019 |
| HUD Group Ltd | Manufacturing | 2024 |
| Huda Trader Limited | Wholesale & retail | 2026 |
| Hulm Estates Ltd | Real estate | 2023 |
| Hulm Stays Ltd | Real estate | 2026 |
| Humanpowers Ltd | Administrative & support | 2019 |
| Humdum UK C.I.C. | Health & social care | 2019 |
| Humourisk CIC | Arts & recreation | 2020 |
| Hunarly Ltd | Information & communication | 2025 |
| Hungarian Food for YOU Limited | Professional & scientific | 2009 |
| Hungerburger Limited | Hospitality | 1985 |
| HUNZLAH7 Limited | Wholesale & retail | 2025 |
| HUS Auto Parts Ltd | Wholesale & retail | 2025 |
| Husayn Property Limited | Real estate | 2024 |
| Husky Merchandise Ltd | Wholesale & retail | 2016 |
| Hussain Halal Meats & Poultry Ltd | Wholesale & retail | 2021 |
| Hussain Property Consortium Ltd | Other services | 2013 |
| Hustle ACT Ltd | Administrative & support | 2025 |
| Huveane Capital Ltd | Financial services | 2017 |
| Hydra Consultancy Services Ltd | Professional & scientific | 2023 |
| Hydra Retail Ltd | Wholesale & retail | 2023 |
| Hydrogen ENT Ltd | Arts & recreation | 2024 |
| HYE Ltd | Wholesale & retail | 2025 |
| Hype Entertainment Group Limited | Arts & recreation | 2026 |
| Hyvogen Ltd | Manufacturing | 2026 |
| HZ Distributions Ltd | Wholesale & retail | 2024 |
| I Education Exchange Ltd | Education | 2021 |
| I F Capittals Ltd | Real estate | 2024 |
| I G Danchev Ltd | Construction | 2013 |
| I G Ignatov Ltd. | Transport & logistics | 2017 |
| I Trade Transport Ltd | Transport & logistics | 2025 |
| I&A SON Ltd | Transport & logistics | 2018 |
| I-Quench Ltd | Manufacturing | 2025 |
| I.A Plumbing & Heating Limited | Construction | 2022 |
| I.G.N. Contracts Limited | Construction | 2011 |
| I.H.T.T.L Ltd | Professional & scientific | 2026 |
| I.O.C. Limited | Administrative & support | 2003 |
| I.T.R. Electrical Co. Limited | Construction | 2014 |
| IA Management Ltd | Real estate | 2021 |
| IB Corporations Ltd | Real estate | 2023 |
| Iboone Ltd | Transport & logistics | 2020 |
| Iboss Barber Limited | Other services | 2023 |
| IBS Platinum Ltd | Health & social care | 2026 |
| IBZ Prestige Ltd | Wholesale & retail | 2020 |
| ICA Transport Ltd | Transport & logistics | 2023 |
| Icare Lodge Limited | Hospitality | 2024 |
| Icare Properties Group Ltd | Real estate | 2023 |
| Icare Resource Limited | Health & social care | 2014 |
| ICC Brickwork Ltd | Construction | 2023 |
| Ice Cream Parties Limited | Arts & recreation | 2014 |
| Icon Build Limited | Construction | 2017 |
| Iconic Home Care Ltd | Health & social care | 2022 |
| Iconic Mist Ltd | Wholesale & retail | 2023 |
| Iconic Reno Limited | Construction | 2025 |
| Iconnect London Ltd | Wholesale & retail | 2016 |
| Icube Dalpro Limited | Professional & scientific | 2018 |
| ID Printworks Ltd | Manufacturing | 2023 |
| ID Properties London Ltd | Construction | 2020 |
| ID Studios Ltd | Professional & scientific | 2024 |
| ID Taxi Centre Ltd | Wholesale & retail | 2018 |
| ID Taxis Ltd | Wholesale & retail | 2018 |
| Ideal Builders & Contractors Ltd | Construction | 2009 |
| Ideal IOT Solution Ltd | Information & communication | 2023 |
| Ideal Management Corps Ltd | Administrative & support | 2020 |
| Ideaopolis Limited | Wholesale & retail | 2024 |
| Ideas Unlimited Limited | Wholesale & retail | 2016 |
| IDH Domestic Appliances Ltd | Other services | 2017 |
| Iems Properties Limited | Real estate | 2022 |
| Ifield & Barrett (Roofing) Limited | Construction | 1972 |
| IFY Fabu Wall Ltd | Construction | 2024 |
| Igct Services Limited | Construction | 2018 |
| IGL Decorator Ltd | Construction | 2023 |
| IGM Construction Ltd | Construction | 2024 |
| Ignite Educators Ltd | Education | 2025 |
| Igonix Technologies Ltd | Information & communication | 2026 |
| Ihsan Enterprises Ltd | Transport & logistics | 2025 |
| II Birmingham Ltd | Wholesale & retail | 2018 |
| II Green Street Ltd | Wholesale & retail | 2018 |
| II Harrow Ltd | Wholesale & retail | 2018 |
| II Ilford Ltd | Wholesale & retail | 2018 |
| II Impressions Ltd | Wholesale & retail | 2018 |
| II Leyton Ltd | Wholesale & retail | 2018 |
| Iizz Ltd | Wholesale & retail | 2025 |
| Ijefine Ltd | Health & social care | 2019 |
| IK Couriers Limited | Transport & logistics | 2014 |
| Ikebiz Limited | Professional & scientific | 2025 |
| Ikon Management Solutions Limited | Real estate | 2013 |
| Ikram Abrar Ltd | Health & social care | 2023 |
| Ilford Group Ltd | Construction | 2025 |
| Ilford Law Chambers Ltd | Professional & scientific | 2022 |
| Ilham Services Limited | Health & social care | 2016 |
| ILI Construct Ltd | Construction | 2023 |
| Illumino Care Limited | Health & social care | 2025 |
| Illuminomedia Limited | Information & communication | 2022 |
| Illy Education Limited | Health & social care | 2025 |
| Ilumo Originals Ltd | Wholesale & retail | 2022 |
| Ilux Properties Limited | Financial services | 2024 |
| Ilxiah CIC | Arts & recreation | 2026 |
| IM Carpenters Ltd | Construction | 2015 |
| Imagine Networks Ltd | Transport & logistics | 2019 |