| Reddy to Train Ltd | Professional & scientific | 2015 |
| Reddys Europe Limited | Hospitality | 2011 |
| Redeco Ltd | Construction | 2020 |
| Redeemed Christian Church of GOD (Rccg) Kings Court Chapel | Other services | 2019 |
| Redeemed Estates Ltd | Real estate | 2025 |
| Redeemer Prayer Group UK Ltd | Health & social care | 2022 |
| Redemeer Company Limited | Health & social care | 2015 |
| Redentor Ltd | Financial services | 2018 |
| Redfish Solutions Limited | Administrative & support | 2005 |
| Redfox Statix Limited | Professional & scientific | 2024 |
| Redhill Farms Limited | Agriculture & fishing | 2004 |
| Redlap Consulting Ltd | Professional & scientific | 2020 |
| Redlap Retreat Ltd | Professional & scientific | 2020 |
| Redlet Property Management Limited | Real estate | 2011 |
| Redmann Holdings Ltd | Administrative & support | 2018 |
| Rednus Limited | Information & communication | 2010 |
| Redoxbox Ltd | Professional & scientific | 2014 |
| Redpaw Security Consultants Ltd | Administrative & support | 2026 |
| Redpoint Engineering Limited | Construction | 2015 |
| Reds Property Maintenance Ltd | Construction | 2013 |
| Redtree Solutions Limited | Wholesale & retail | 2005 |
| Redu Ltd | Professional & scientific | 2025 |
| Redway Networks Ltd | Wholesale & retail | 2015 |
| Reece International Ltd | Manufacturing | 2022 |
| Reed Bidco Limited | Financial services | 2026 |
| Reedconsulting Ltd | Professional & scientific | 2020 |
| Reeds Global Ltd | Construction | 2025 |
| Reehal & Co. Estates and Assets Ltd | Real estate | 2025 |
| Reelmotion Ltd | Information & communication | 2014 |
| Reemas Ltd | Manufacturing | 2021 |
| Reena Elad Ltd | Professional & scientific | 2026 |
| Reesol 2 Ltd | Administrative & support | 2013 |
| Reeve Plumbing & Heating Limited | Construction | 2011 |
| Refillit Ltd | Other services | 2023 |
| Refined Coachworks Ltd | Wholesale & retail | 2019 |
| Reflecting Limited | Information & communication | 2013 |
| Reflections Refinish Ltd | Construction | 2018 |
| Reframe Entertainment Limited | Professional & scientific | 2026 |
| Refurb Prime Buildings Limited | Construction | 2022 |
| Regains Beauty & Aesthetics Ltd | Other services | 2023 |
| Regal Booths Events Ltd | Administrative & support | 2025 |
| Regal Dog Parlour Ltd | Other services | 2023 |
| Regal Envy Ltd | Other services | 2020 |
| Regal Prestige Auto Group Limited | Wholesale & retail | 2024 |
| Regal Ridge Properties Limited | Construction | 2024 |
| Regal UK 247 Properties Ltd | Real estate | 2021 |
| Regan Consulting Ltd | Professional & scientific | 2025 |
| Regan Ellis Ltd | Arts & recreation | 2023 |
| Regcheck Ltd | Other services | 2024 |
| Regd Limited | Real estate | 2023 |
| Regency Property & Lettings Ltd | Real estate | 2026 |
| Regency Roofing and Guttering Ltd | Construction | 2026 |
| Regency Systems Limited | Professional & scientific | 2004 |
| REGENER8 Property Services Limited | Construction | 2021 |
| Regenersis (Germany) Ltd | Administrative & support | 1999 |
| Reggia Ltd | Manufacturing | 2024 |
| Regis Garonwhite Retail Ltd | Wholesale & retail | 2022 |
| Regisina Company Ltd | Administrative & support | 2025 |
| Rego Holdings Limited | Hospitality | 2023 |
| Rego Homes Limited | Construction | 2021 |
| Rego Wealth Limited | Real estate | 2016 |
| Regus Silbury Ltd | Administrative & support | 2025 |
| Regza Limited | Wholesale & retail | 2026 |
| Rehealth ME Ltd | Wholesale & retail | 2020 |
| Rehoboth PCP Ltd | Other services | 2016 |
| Rehoboth Properties (UK) Limited | Construction | 2016 |
| Rehoboth Property Investment Ltd | Real estate | 2020 |
| Rehoboth Social Media Ltd | Wholesale & retail | 2024 |
| Rehoboth Support Services Limited | Health & social care | 2019 |
| Rehsaw Engineering Ltd | Professional & scientific | 2021 |
| Reid & Co. Corporate Services Limited | Professional & scientific | 1988 |
| Reid & Co. Professional Services Limited | Professional & scientific | 1997 |
| Reid Consulting Associates Limited | Professional & scientific | 2018 |
| Reiger Suspension UK Limited | Wholesale & retail | 2013 |
| Reign Hair and Beauty Ltd | Other services | 2018 |
| Reignpark Limited | Health & social care | 2014 |
| Reijets Ltd | Other services | 2019 |
| Reimagined Solutions Ltd | Real estate | 2025 |
| Reimagining Criminal Justice C.I.C. | Professional & scientific | 2025 |
| Reimundo Limited | Construction | 2026 |
| Reinforced Car Components Ltd | Manufacturing | 2021 |
| Reinvention Consulting Ltd | Professional & scientific | 2016 |
| Reiroy Global Limited | Professional & scientific | 2026 |
| Reis Tech Ltd | Information & communication | 2022 |
| Rejis Ltd | Real estate | 2019 |
| Rejoice HQ Ltd | Other services | 2026 |
| Relationships Milton Keynes Ltd | Extraterritorial | 2025 |
| Relativecare Ltd | Information & communication | 2016 |
| Relax & Strive Limited | Manufacturing | 2025 |
| Reliable Associates Ltd | Other services | 2012 |
| Reliable Cleaning Services Limited | Households | 2018 |
| Reliable Lettings and Developments Ltd | Real estate | 2022 |
| Reliable Power Solutions Group Limited | Professional & scientific | 2012 |
| Reliable Support Services Limited | Other services | 2019 |
| Reliable Vehicles Limited | Wholesale & retail | 1973 |
| Relief Seeds of Change | Health & social care | 2025 |
| Relocate Property Services Limited | Professional & scientific | 2019 |
| Remal Construction Ltd | Construction | 2026 |
| Rembeck Properties Limited | Real estate | 2022 |
| Remec Engineering Services (Burnley) Limited | Manufacturing | 1994 |