| RMC Retail Limited | Professional & scientific | 2019 |
| RMG Professional Limited | Professional & scientific | 2015 |
| Rmss Property Ltd | Real estate | 2023 |
| RMW (London) Ltd | Construction | 2023 |
| RNB Wines Ltd | Wholesale & retail | 2025 |
| Rnrapps Limited | Information & communication | 2012 |
| Road Freight Investments Limited | Professional & scientific | 1987 |
| ROAD2RECOVERY Auto Service Centre Ltd | Wholesale & retail | 2026 |
| ROB Cross Darts Limited | Arts & recreation | 2017 |
| ROB Davis Limited | Professional & scientific | 2016 |
| ROB Gill Bids Limited | Administrative & support | 2010 |
| Robentom Ltd | Hospitality | 2025 |
| Robert Allen Media Ltd | Information & communication | 2024 |
| Robert Ellingham Film Services Ltd | Information & communication | 2022 |
| Robert Gilham Ltd | Wholesale & retail | 2019 |
| Robert Ryall Associates Limited | Professional & scientific | 2010 |
| Roberto's Valeting Services Ltd | Other services | 2026 |
| Roberts Electrical Installations Ltd | Construction | 2012 |
| Roberts Q and Company Limited | Wholesale & retail | 2018 |
| Robertson Security Consulting Ltd | Information & communication | 2010 |
| Robin AI Series B Co-Investment SPV LP | | 2023 |
| Robin Baillie Consulting Limited | Professional & scientific | 2022 |
| Robins Close London Colney Limited | Households | 1998 |
| Robinson Arts & Education Ltd | Education | 2026 |
| Robinson Tree Services Limited | Agriculture & fishing | 2002 |
| Robinsons Electrical Services Ltd | Construction | 2010 |
| Robomercato Limited | Information & communication | 2025 |
| Robot Center Ltd | Manufacturing | 2011 |
| Roboz Limited | Information & communication | 2025 |
| Robyrne Investments Limited | Real estate | 2020 |
| ROC (Consultancy) Limited | Professional & scientific | 2023 |
| Roca Club Ltd | Wholesale & retail | 2025 |
| Roccamora UK Limited | Administrative & support | 2009 |
| Rock Analysis Ltd | Professional & scientific | 2024 |
| Rock and Road Bikes Limited | Wholesale & retail | 2006 |
| Rocket Capital LP | | 2021 |
| Rockwell Developments Limited | Construction | 2024 |
| Rodells Contracts Limited | Construction | 2025 |
| Rodells Limited | Construction | 1976 |
| Rodeo Stunts Limited | Arts & recreation | 2018 |
| Roger & Arthur Limited | Information & communication | 2017 |
| Rohrmoos Ltd | Professional & scientific | 2025 |
| Rokoko London Ltd | Wholesale & retail | 2016 |
| Roksana Hussein Limited | Professional & scientific | 2018 |
| ROL (Holdings) Limited | Professional & scientific | 2015 |
| ROL Groundworks Limited | Construction | 2009 |
| ROL Planthire Limited | Administrative & support | 2007 |
| Roladhealth (UK) Limited | Health & social care | 2009 |
| Roland Construction Limited | Construction | 2009 |
| Roland Division Limited | Construction | 2020 |
| Rolfe Contracting Limited | Construction | 1997 |
| Rolling Holdings Limited | Real estate | 2025 |
| Roman Theatre Limited | Arts & recreation | 1967 |
| Romans Limited | Wholesale & retail | 2007 |
| Romarsol Limited | Professional & scientific | 2012 |
| Romulus Advisory (Redbourn) Limited | Financial services | 2021 |
| Ronayne Communications Limited | Professional & scientific | 2025 |
| Rongli 288 Limited | Hospitality | 2025 |
| Ronnet Ltd | Administrative & support | 2014 |
| Roofing Supermarket Limited | Extraterritorial | 2016 |
| Root Design London Ltd | Professional & scientific | 2024 |
| Roots & Dreams Ltd | Agriculture & fishing | 2023 |
| Rose & DEE Limited | Hospitality | 2019 |
| Rose and Lily Limited | Real estate | 2021 |
| Rose Cottage Farm Ltd | Real estate | 2020 |
| Rose of Houses Ltd | Real estate | 2024 |
| Rose Pilkington Studio Limited | Other services | 2022 |
| Roseanne Jackman Ltd | Arts & recreation | 2021 |
| Roseberry Estates Limited | Real estate | 1993 |
| Rosefinch Property Company Limited | Real estate | 2005 |
| Rosemarie Grant Designs Ltd | Manufacturing | 2017 |
| Roshea Consulting Limited | Professional & scientific | 2024 |
| Rosie Parsons Private Travel Ltd | Administrative & support | 2025 |
| Rosies Green Cleaning Services Ltd | Other services | 2025 |
| Roslyn Way Ltd | Real estate | 2024 |
| Ross Removals Ltd | Transport & logistics | 2024 |
| Rossa Consulting Limited | Wholesale & retail | 2008 |
| Rossmoyne Ltd | Professional & scientific | 2025 |
| Rotae Vehicle Fire Investigations Ltd | Public administration | 2025 |
| Rothamsted View Management Limited | Households | 2024 |
| Round 1 Boxing Academy Ltd | Arts & recreation | 2024 |
| Rovas Plumbing Ltd | Construction | 2020 |
| Rowan Close Maintenance Company Limited | Extraterritorial | 1987 |
| Rowley Fine Art Auctioneers and Valuers Limited | Administrative & support | 2000 |
| Rowshon Restaurant Ltd | Hospitality | 2013 |
| Royston Homes Ltd | Construction | 2017 |
| Rozalia Homes Ltd | Real estate | 2024 |
| RPM Electrical (Herts) Ltd | Construction | 2023 |
| RPM Plumbing & Heating (Herts) Ltd | Construction | 2020 |
| RR E- Ventures Ltd | Information & communication | 2014 |
| RRB Constructions Limited | Construction | 2011 |
| RRC Systems Accounting Ltd | Professional & scientific | 2008 |
| RS Cardioworks Ltd | Health & social care | 2025 |
| Rt&Ljw Limited | Administrative & support | 2001 |
| RTF24 Merry Wives Limited | Arts & recreation | 2024 |
| RTF24 Secret Garden Limited | Arts & recreation | 2024 |
| RTI Auto Services Limited | Manufacturing | 2015 |
| Rubeus Eight Limited | Financial services | 2017 |
| Rubeus Eight Private Finance Limited | Administrative & support | 2018 |
| Rubeus Eight Ventures Limited | Administrative & support | 2021 |