| Honey Slice Bakery Ltd | Manufacturing | 2020 |
| Honey's Swim School Ltd | Education | 2025 |
| Honeyball Smith Consulting Limited | Professional & scientific | 2024 |
| HOP Import Ltd | Wholesale & retail | 2024 |
| Hope IS CIC | Hospitality | 2022 |
| Hope Just Limited | Wholesale & retail | 2014 |
| Hope's Healthy Treats Ltd | Wholesale & retail | 2021 |
| Hopkins & Co Holdings Ltd | Real estate | 2017 |
| Horgan Estates Ltd | Extraterritorial | 2019 |
| Horizh Limited | Information & communication | 2026 |
| Horizon Films Ltd | Information & communication | 2021 |
| Horlock Properties Limited | Real estate | 2004 |
| Hornchurch Football Club Limited | Arts & recreation | 2013 |
| Hornchurch Scaffolding Services Limited | Construction | 2016 |
| Hornchurch Street Building & Refurbishment Ltd | Construction | 2024 |
| Hornchurch Street Plumbing & Heating Ltd | Construction | 2024 |
| Horndon Holdings Limited | Hospitality | 2018 |
| Hornsby Cars Ltd | Wholesale & retail | 2024 |
| Horwood Limited | Construction | 2017 |
| Hot TUB Chemicals Direct Limited | Other services | 2021 |
| Hot Tubs of London Limited | Other services | 2020 |
| Hotelkitty Limited | Agriculture & fishing | 2025 |
| Houghton & SON Limited | Construction | 1993 |
| Houghton & SON Properties Ltd | Real estate | 2018 |
| Houghton Homes Group Ltd | Real estate | 2016 |
| Houghton Homes Ltd | Real estate | 2018 |
| Houghton Homes Partnership LLP | | 2021 |
| Hounds at Home Ltd | Agriculture & fishing | 2019 |
| House of Bling Interiors Ltd | Wholesale & retail | 2020 |
| House of Hatton Limited | Wholesale & retail | 2015 |
| House of Invicta Ltd | Professional & scientific | 2025 |
| House of Loca Ltd | Arts & recreation | 2025 |
| House of Savin Limited | Wholesale & retail | 2018 |
| House of Wells Limited | Health & social care | 2008 |
| Housebook Ltd | Real estate | 2020 |
| Hovefields Holding Limited | Real estate | 2016 |
| Hovefields Property Services Limited | Real estate | 2017 |
| HOW to Make the Headlines Limited | Other services | 2021 |
| Hows Your Health Ltd | Health & social care | 2026 |
| Hoyanda Limited | Wholesale & retail | 2025 |
| HPK Construction Limited | Construction | 2020 |
| HPL Group Limited | Real estate | 2022 |
| HPR Online Ltd | Wholesale & retail | 2026 |
| HR Plumbing Ltd | Construction | 2026 |
| HRB Plumbing and Heating Limited | Construction | 2017 |
| HRC Digital Ltd | Professional & scientific | 2026 |
| HRG (Holdings) Limited | Real estate | 2017 |
| HRS Drainage Ltd | Construction | 2019 |
| Hrus Ltd | Wholesale & retail | 2020 |
| HSE Services Ltd | Construction | 2015 |
| Hsld Research Ltd | Professional & scientific | 2022 |
| HSS Physiotherapy Services Limited | Financial services | 2022 |
| Hsskins Limited | Other services | 2024 |
| HT Hightide Limited | Other services | 2021 |
| HTL Essex Limited | Other services | 2016 |
| Hubcluster Ltd | Real estate | 2013 |
| HUC Rail Limited | Professional & scientific | 2014 |
| Hudson Mechanical Limited | Construction | 2024 |
| Hudson Media UK Ltd | Arts & recreation | 2019 |
| Hugh Newman Limited | Other services | 2023 |
| Hughes Heating & Plumbing Ltd | Construction | 2015 |
| Hugo Anthony Consulting Limited | Professional & scientific | 2025 |
| Hugs and Blisses Events Limited | Hospitality | 2022 |
| Hummingbirds Care Ltd | Health & social care | 2019 |
| HUN Services Ltd | Wholesale & retail | 2025 |
| Hushylart Care and Services Ltd | Health & social care | 2025 |
| Husmitt Ltd | Wholesale & retail | 2025 |
| Hy&Co Services Ltd | Administrative & support | 2023 |
| Hy-Way Systems Ltd. | Professional & scientific | 1995 |
| Hyde Aerial Satellites Ltd | Extraterritorial | 2013 |
| Hyde Audio and Visual Solutions Limited | Information & communication | 2011 |
| Hyde AV Solutions Ltd | Extraterritorial | 2013 |
| Hyde Maintenance Ltd | Professional & scientific | 2018 |
| Hydro Hydro Ltd | Wholesale & retail | 2018 |
| Hylaird Solutions Limited | Other services | 2017 |
| I & G Automotive Ltd | Wholesale & retail | 2016 |
| I & N Contractors Ltd | Construction | 2019 |
| I & O Solution Limited | Construction | 2017 |
| I AM TIM Hilton Limited | Extraterritorial | 2012 |
| I DID That Ltd | Information & communication | 2010 |
| I F E Airfreight Holdings Limited | Financial services | 2020 |
| I F E Global Logistics (North) Limited | Transport & logistics | 2024 |
| I F E Global Logistics (UK) Limited | Transport & logistics | 1999 |
| I F E Global Logistics Property Limited | Real estate | 2024 |
| I for Ideas Limited | Administrative & support | 2013 |
| I Generate Ltd | Administrative & support | 2023 |
| I Love Blinds (UK) Limited | Wholesale & retail | 2012 |
| I Love Decaf Ltd | Wholesale & retail | 2021 |
| I R Installations Limited | Construction | 2006 |
| I V Services (UK) Ltd | Construction | 2008 |
| I&C Trading Limited | Other services | 2015 |
| I&I Utilities Ltd | Construction | 2025 |
| I-Consul Limited | Information & communication | 2008 |
| I-Sec UK Limited | Administrative & support | 2005 |
| I. Curate Ltd | Information & communication | 2023 |
| I.M.C. Holdings Limited | Real estate | 1991 |
| I.P.L Interiors Limited | Construction | 2017 |
| I.Seferi Drylining Ltd | Construction | 2026 |
| IB City Consultant Limited | Financial services | 2012 |
| IB Trading Limited | Water & waste | 2021 |