| Digital Capital Markets Limited | Administrative & support | 2007 |
| Digital Communications Strategy Ltd | Professional & scientific | 2025 |
| Digital Echo Ltd | Manufacturing | 2000 |
| Digital Inroads Limited | Information & communication | 2024 |
| Digital Place Futures Limited | Professional & scientific | 2026 |
| Digital Reshift Ltd | Professional & scientific | 2022 |
| Digital Salmon Ltd | Information & communication | 2017 |
| Digital Ship Events Limited | Information & communication | 2012 |
| Digital Ship Limited | Information & communication | 2000 |
| Diligenter Limited | Professional & scientific | 2017 |
| Dilley Studio Limited | Professional & scientific | 2017 |
| Dime Cleaning Ltd | Administrative & support | 2024 |
| Dimos Ltd | Professional & scientific | 2018 |
| Dipam Investments Ltd | Real estate | 2019 |
| Direct Source Limited | Professional & scientific | 1998 |
| Direct Trade Investment Limited | Wholesale & retail | 2016 |
| Directors CUT Films West Limited | Information & communication | 2017 |
| Disabled Drive (Mobility Care) Limited | Agriculture & fishing | 1995 |
| Discorso Speakers Bureau Limited | Arts & recreation | 2023 |
| Disinfection Services Watford Limited | Administrative & support | 2015 |
| Disruptive Bytes Ltd | Professional & scientific | 2025 |
| Disruptive Training Limited | Professional & scientific | 2006 |
| Distributed Systems Management Limited | Professional & scientific | 2023 |
| District & Metropolitan Company Limited | Manufacturing | 1993 |
| Diva Care Limited | Health & social care | 1993 |
| Divetimaging Ltd | Public administration | 2023 |
| Divine Dental Care Limited | Health & social care | 2013 |
| Divine Union Limited | Information & communication | 2019 |
| Divisha Pharma Ltd | Health & social care | 2019 |
| Dj&Sons PVT Ltd | Real estate | 2025 |
| Djbm Ltd | Information & communication | 2023 |
| DJG IT Ltd | Professional & scientific | 2007 |
| Djgilbert & Sons Ltd | Administrative & support | 2017 |
| DJH Fine Art Packers Limited | Administrative & support | 2007 |
| DJM Catering Limited | Hospitality | 2025 |
| DJS Building Solutions Ltd | Construction | 2016 |
| DK Home Refurbishment Limited | Construction | 2019 |
| DK Quality Construction Ltd | Construction | 2026 |
| DKW Investments Limited | Real estate | 2015 |
| DL Management Consultancy Ltd | Administrative & support | 2011 |
| DLA Town Planning Solutions Limited | Professional & scientific | 2016 |
| DM Angel Syndicate Seed LLP | | 2021 |
| DM Communications Limited | Construction | 2023 |
| DM Herts Property Ltd | Real estate | 2020 |
| Dm's Lighting Ltd | Wholesale & retail | 2025 |
| Dmcrazyapps Ltd | Administrative & support | 2025 |
| DMD Electrics Ltd | Energy | 2007 |
| DOB Electrical Limited | Construction | 2023 |
| Dobbs Services Ltd | Professional & scientific | 2014 |
| DOC Plumbing, Heating & GAS Ltd | Construction | 2021 |
| DOC Polo Breeding Ltd | Agriculture & fishing | 2021 |
| Doctor.D.Aesthetic Limited | Health & social care | 2022 |
| Doctors.Digital Ltd | Information & communication | 2024 |
| Dodd Technologies Limited | Information & communication | 2025 |
| Dog and Jones Ltd | Hospitality | 2026 |
| Dog Cat Ltd | Professional & scientific | 2019 |
| DOL Fitness Ltd | Arts & recreation | 2023 |
| Dolan and Co Barbershop Ltd | Other services | 2024 |
| Dolomite Solutions Limited | Information & communication | 2014 |
| Domah Developments Ltd | Construction | 2025 |
| Domek Ltd | Real estate | 2024 |
| Donndanco Limited | Education | 2019 |
| Donoghues Legal Costs Limited | Professional & scientific | 2016 |
| Donostia Holdings Limited | Professional & scientific | 2015 |
| Donostia Restaurants Ltd | Hospitality | 2011 |
| Don’T Forget Your Jacket Ltd | Hospitality | 2024 |
| Doorprop Ltd | Households | 2020 |
| Doors London Limited | Administrative & support | 2010 |
| DOR-2-DOR (Franchise) Ltd. | Professional & scientific | 2000 |
| DOR-2-DOR Limited | Professional & scientific | 1994 |
| Dormant Property Ltd | Real estate | 2025 |
| Dortons Management Limited | Construction | 2017 |
| Doruk Architecture Design Ltd | Construction | 2025 |
| Doucallia Investments Limited | Real estate | 2011 |
| Doug Sawyer Services Ltd | Construction | 2018 |
| Douglas Angus Consultancy & Training Ltd | Administrative & support | 2016 |
| Douglas Forsyth Developments Limited | Real estate | 2017 |
| Dovehouse Holdings Limited | Financial services | 2017 |
| Dovelle Limited | Health & social care | 2025 |
| Dowling Development & Construction Limited | Construction | 2005 |
| Downforce Racing Simulation Ltd | Arts & recreation | 2016 |
| Downlo Developments Ltd | Information & communication | 2016 |
| DP Real Property Investment Ltd | Real estate | 2026 |
| DPK Associates Limited | Professional & scientific | 2006 |
| Dprw Solutions Limited | Professional & scientific | 2023 |
| DPT Consulting Ltd | Professional & scientific | 2022 |
| DR Canary Limited | Information & communication | 2019 |
| DR EMS Performance Ltd | Education | 2025 |
| DR Esra Gumus Ltd | Health & social care | 2021 |
| DR JO Wood Psychologist Limited | Professional & scientific | 2025 |
| DR Khalid Mirza Ltd | Health & social care | 2011 |
| DR Legumes CIC | Hospitality | 2017 |
| DR Michael Cannell Ltd | Health & social care | 2021 |
| DR MP Healthcare Ltd | Health & social care | 2026 |
| DR N Anyamene Limited | Health & social care | 2016 |
| DR Nikki DE Taranto Ltd | Health & social care | 2016 |
| DR S Clinics Ltd | Health & social care | 2022 |
| DR. Azad Ghuran Ltd | Health & social care | 2017 |
| Draft Horse Limited | Public administration | 2024 |
| Draga Limited | Construction | 2023 |