| Hornets Nest Ltd | Real estate | 2017 |
| Hosted IT Limited | Information & communication | 2015 |
| Hosted IT Property 1 Limited | Real estate | 2020 |
| Hosted IT Property 3 Limited | Real estate | 2020 |
| Hosted-Infotech Ltd | Information & communication | 2025 |
| Hotspur Hire Recovery and Maintenance Ltd | Administrative & support | 2024 |
| Hotze and Anisman Ltd | Manufacturing | 2024 |
| Houghtons (Hsllaw) Limited | Professional & scientific | 1997 |
| Houndwell Ltd | Wholesale & retail | 2026 |
| Hour House Accountants Ltd | Administrative & support | 2016 |
| House of Hojati Ltd | Wholesale & retail | 2024 |
| House of Licenses Limited | Other services | 2025 |
| House of Ninjas Ltd | Information & communication | 2020 |
| House of Phulkari Ltd | Wholesale & retail | 2025 |
| Housebuilders.London Limited | Extraterritorial | 2020 |
| Hove Park Apartments (Goldstone) Limited | Construction | 2025 |
| Howard Atkins Associates Limited | Professional & scientific | 2012 |
| Howard Atkins Limited | Professional & scientific | 1999 |
| HP Investors Limited | Real estate | 2016 |
| HP Solutions Limited | Information & communication | 2014 |
| HR Path UK Ltd | Administrative & support | 2014 |
| HS Capital Group Ltd | Financial services | 2023 |
| Hub 38 Limited | Hospitality | 2023 |
| Hudson Northwood Limited | Real estate | 2019 |
| Hudson Place Limited | Hospitality | 2021 |
| Hueristic Limited | Health & social care | 2025 |
| Humanseen Global Ltd | Information & communication | 2023 |
| Hundred Ltd | Wholesale & retail | 2022 |
| Hunt Technology Limited | Administrative & support | 1990 |
| Hunterlodge Group Limited | Professional & scientific | 2011 |
| Hunterlodge Holdings Limited | Financial services | 2025 |
| Huntingdon Wells Ltd | Construction | 2023 |
| Hurlingham Court Limited | Hospitality | 1985 |
| Hydeaway Spa Ltd | Other services | 2011 |
| Hydroformer Project Management Services Limited | Information & communication | 2014 |
| Hyperion Sound and Music Ltd | Information & communication | 2013 |
| Hypgage Ltd | Information & communication | 2023 |
| I DO Handmade Ltd | Wholesale & retail | 2022 |
| I.A. Dermatology Limited | Health & social care | 2013 |
| I.R.C.M. International Group of Researchers and Development for Complimentary Medicine Limited | Health & social care | 2008 |
| Iaderma Ltd | Manufacturing | 2026 |
| IAN Hall Associates Limited | Real estate | 1999 |
| IAN Hills Limited | Construction | 2001 |
| Ianb Foto Limited | Professional & scientific | 2010 |
| Iconix Design and Build Ltd | Construction | 2025 |
| Iconix Grande Limited | Construction | 2026 |
| Iconix Grove Lane Ltd | Construction | 2025 |
| Iconix Homes Limited | Construction | 2025 |
| Iconos Group Limited | Professional & scientific | 2021 |
| Icure Solutions Ltd | Health & social care | 2013 |
| Idcc Ltd | Information & communication | 2019 |
| Ideal Design & Developments Ltd | Construction | 2007 |
| Ideal Window Cleaning Franchise Limited | Administrative & support | 2013 |
| Ideal Window Cleaning Limited | Administrative & support | 2014 |
| IDG AS Ventures Ltd | Manufacturing | 2024 |
| IE3D Ltd | Arts & recreation | 2018 |
| IEL Gynae Care Ltd | Health & social care | 2023 |
| IFS Trustees Limited | Other services | 2019 |
| Iiexchange Ltd | Administrative & support | 2014 |
| IIH Global Limited | Information & communication | 2023 |
| IJR Properties Ltd | Real estate | 2015 |
| Ikaros Bristol Limited | Transport & logistics | 2020 |
| Ikaros SW Limited | Transport & logistics | 2019 |
| Ikarus Pro Services Ltd | Construction | 2019 |
| Ikhoi Tech Limited | Information & communication | 2018 |
| Iluka London Limited | Manufacturing | 2016 |
| Imadoer Limited | Construction | 2016 |
| Impact Activity Clubs Ltd | Education | 2021 |
| Imperial Healthcare Training Academy Limited | Professional & scientific | 2025 |
| Imprint Digital Limited | Information & communication | 2005 |
| Imprint Promotional Services Ltd | Wholesale & retail | 2010 |
| Imprint Properties Limited | Real estate | 2020 |
| Impromax Limited | Professional & scientific | 2008 |
| Improve Ltd | Information & communication | 2023 |
| IMS Vehicle Solutions Ltd | Wholesale & retail | 2013 |
| IMT Securities Limited | Construction | 2018 |
| IN Warehousing and Logistics Ltd | Transport & logistics | 2019 |
| In-Vision TV Facilities Limited | Information & communication | 2009 |
| Incisive Wealth Strategies LLP | | 2005 |
| Inclusionspecialistsforsen Ltd | Professional & scientific | 2025 |
| Inclusive Work Ltd | Professional & scientific | 2017 |
| Independence Ventures Ltd | Real estate | 2017 |
| Indie Media Limited | Information & communication | 2012 |
| Indigominds Assessment Services Limited | Health & social care | 2026 |
| Inficube Mart Ltd | Wholesale & retail | 2022 |
| INFINITE8 Limited | Real estate | 2017 |
| Infinity Fire Protection Limited | Public administration | 2017 |
| Inflection Associates Limited | Real estate | 2017 |
| Infotix Limited | Professional & scientific | 2025 |
| Infuzions Ltd | Hospitality | 2019 |
| Ingen Management Limited | Professional & scientific | 2013 |
| Inglemanor Limited | Professional & scientific | 2002 |
| Inglis Properties Limited | Construction | 2025 |
| INI Limited | Professional & scientific | 2019 |
| Innotek Solutions Ltd | Information & communication | 2008 |
| Innova Group Holdings Limited | Financial services | 2024 |
| Innovant Network Ltd | Information & communication | 2019 |
| Inplico Ltd | Professional & scientific | 2022 |
| Inqalabi Tradenest Limited | Wholesale & retail | 2025 |
| Insight Analytics Ltd | Information & communication | 2009 |