| RCM Automotive Limited | Administrative & support | 2024 |
| RCM Freelance Ltd | Administrative & support | 2026 |
| RCM Group Holdings Ltd | Financial services | 2026 |
| RCM Permanent Ltd | Administrative & support | 2026 |
| RCM Site Services Ltd | Construction | 2026 |
| RDR Dassaur Properties Ltd | Real estate | 2020 |
| Readly UK Limited | Information & communication | 2013 |
| Real Faces Limited | Other services | 2022 |
| Real Time Telecoms Limited | Information & communication | 2020 |
| Reasonable Discourse Ltd | Information & communication | 2022 |
| Rebel Reformer Ltd | Manufacturing | 2025 |
| Rebeldot UK Limited | Information & communication | 2025 |
| Recco Limited | Manufacturing | 2019 |
| Reconstruction Midlands Limited | Professional & scientific | 2021 |
| Recruitmentland UK Limited | Information & communication | 2013 |
| Red Band Limited | Extraterritorial | 2009 |
| Red C Mobile Ltd | Information & communication | 1997 |
| Red Carpentry Contractors Limited | Construction | 2022 |
| Red Horse Close Management Company Limited | Households | 2017 |
| Red Horse Heating Limited | Construction | 2022 |
| Red Panda Events Ltd | Arts & recreation | 2025 |
| Red Road Consultancy Ltd | Professional & scientific | 2021 |
| Red Road Pizza Company Limited | Hospitality | 2017 |
| Red Shed Media Limited | Information & communication | 2014 |
| Redbarn Quantity Surveyors Ltd | Professional & scientific | 2015 |
| Redbrick & Partners Ltd | Real estate | 2026 |
| Redcotts Properties Limited | Real estate | 2007 |
| Reddinghurst Limited | Professional & scientific | 2014 |
| Redhill Capital Group Limited | Financial services | 2025 |
| Redhill Mount Limited | Administrative & support | 1980 |
| Redscree Ltd | Construction | 2024 |
| Redsource Consulting Limited | Professional & scientific | 2025 |
| Reflex Integration Training Ltd | Education | 2024 |
| Reflexrule Limited | Professional & scientific | 1985 |
| Regdoor Global Holdings Limited | Financial services | 2025 |
| Regency Business Services Limited | Professional & scientific | 2014 |
| Regenerative LLP | | 2022 |
| Regent Bathrooms Limited | Wholesale & retail | 2009 |
| Rehal Consultancy Services Limited | Information & communication | 2022 |
| Reign Innovation Ltd | Information & communication | 2026 |
| Rekha Consultancy Ltd | Administrative & support | 2012 |
| Rellew Finance Limited | Real estate | 1969 |
| Renaissance PR Ltd | Professional & scientific | 2015 |
| Renashield Limited | Real estate | 1966 |
| Renault Truck Commercials Limited | Wholesale & retail | 1934 |
| Renault Trucks UK Ltd | Wholesale & retail | 1936 |
| Renewable Sites Ltd | Construction | 2022 |
| Renovator Limited | Construction | 1995 |
| Renroh Associates Limited | Professional & scientific | 2013 |
| Rent Learn Return Ltd | Education | 2010 |
| Reprobates Media Ltd | Arts & recreation | 2024 |
| Res-Distribution Limited | Construction | 2019 |
| Researchcraft Limited | Professional & scientific | 1997 |
| Resilience Aesthetics & Wellness Ltd | Health & social care | 2023 |
| Resilience Health Solutions Ltd | Health & social care | 2022 |
| Resistant AI Limited | Information & communication | 2024 |
| Resolute Designs Ltd | Wholesale & retail | 2019 |
| Resolution Software Limited | Information & communication | 2016 |
| Retail Consultants Limited | Information & communication | 2004 |
| Retail Magic Ltd | Information & communication | 2024 |
| Retina Design Studio Ltd | Professional & scientific | 2021 |
| Retirement Security (Milton Keynes) Limited | Construction | 1987 |
| Retirement Security (Reading) Limited | Construction | 1988 |
| Retirement Security Limited | Construction | 1982 |
| Reubicon Contracts Limited | Information & communication | 2019 |
| Reubicon Estates Limited | Real estate | 2019 |
| Reubicon Transport Limited | Transport & logistics | 2021 |
| Revo-Riding Limited | Wholesale & retail | 1997 |
| Revotech Systems Limited | Financial services | 2025 |
| REY Energy Ltd | Construction | 2022 |
| REY Renewable Energy Limited | Construction | 2026 |
| Reyco Productions Ltd | Extraterritorial | 2015 |
| Reymond Langton Design Ltd | Professional & scientific | 2002 |
| Reymond Langton Limited | Professional & scientific | 2015 |
| RF Admin Services Limited | Administrative & support | 2018 |
| RF Mechanical Services UK Ltd | Wholesale & retail | 2023 |
| RFR Festivals Limited | Hospitality | 2025 |
| Rh&P Ltd | Manufacturing | 2017 |
| Rhealyn Assets Ltd | Construction | 2021 |
| Rhealyn Ltd | Health & social care | 2020 |
| Riaz Investments Ltd | Real estate | 2012 |
| Riben Construction Ltd | Construction | 2024 |
| Richard Collings Limited | Real estate | 1979 |
| Richard Garrett & Sons Limited | Manufacturing | 1998 |
| Richard Hall Stunts Ltd | Arts & recreation | 2021 |
| Richard Morris Racing Ltd | Professional & scientific | 2020 |
| Richard Sore Ltd | Real estate | 2018 |
| Richard Woolley Limited | Real estate | 2025 |
| Richard's Pharma (Holdings) Limited | Financial services | 2020 |
| Richard's Pharma Limited | Financial services | 2005 |
| Richmichris Limited | Financial services | 2020 |
| Richminster Properties Limited | Real estate | 2002 |
| Richpenny Limited | Professional & scientific | 2019 |
| Richsmart Homes Ltd | Construction | 2019 |
| Ridgeway Ecology Limited | Professional & scientific | 2014 |
| Riding Revolution Limited | Extraterritorial | 1996 |
| Rigvo Ltd | Wholesale & retail | 2022 |
| Rippers Golf Ltd | Professional & scientific | 2020 |
| Rise Comms Limited | Professional & scientific | 2017 |
| Riviera Property Limited | Construction | 2011 |