| Crown Cleaning Management Limited | Plymouth | 2018 |
| Crown Environmental Solutions Limited | Birmingham | 2022 |
| Crown Waste Limited | Nuneaton | 2004 |
| Crown Waste Management (Leeds) Ltd | Leeds | 2026 |
| Crown Waste Management Limited | Nuneaton | 2004 |
| Crown Waste OIL Limited | London | 2024 |
| Crownloch Limited | Beith | 2013 |
| Crows Nest Aggregates and Stone Supplies Ltd | Wakefield | 2018 |
| Croydon Waste Ltd | London | 2020 |
| Croydon Wood Recycling Limited | London | 2015 |
| CRS (Eastern) Limited | Peterborough | 2009 |
| CRS Services (UK) Ltd | Lincoln | 2014 |
| CRS Tanks Ltd | Littlehampton | 2014 |
| Crucial Environmental Limited | Worthing | 2012 |
| Crucial Recycling Ltd | Wednesbury | 2022 |
| Crucial Recycling Yorkshire Ltd | Leeds | 2025 |
| Crucible Gypsum Recycling Limited | Bristol | 2017 |
| Crumps Environmental Limited | Hertford | 2023 |
| Crusader Displays Limited | Preston | 1973 |
| Crux Crew Ltd | Cardiff | 2026 |
| Crynant Skips and Recycling Ltd | Neath | 2003 |
| Crystal Clear Drainage and Plumbing Limited | London | 2025 |
| Crystal Clear Products (2000) Ltd | Colchester | 1999 |
| Crystal Clear Window Cleaning Ltd | Worcester | 2015 |
| Crystal Clearance Services Ltd | Ashford | 2019 |
| Crystal Environmental Services Ltd | Ilkeston | 2006 |
| Crystal Oils Ltd | London | 2025 |
| Crystal Pure Water International Ltd | Leicester | 2020 |
| Crystal Water Compliance Ltd | Dunblane | 2022 |
| Crystal Water Filters Ltd | Harrow | 2025 |
| Crystal Water Group Limited | York | 2020 |
| Crystal Water Services Ltd | Luton | 2018 |
| Crystal Water Technologies Ltd | Derby | 2013 |
| Crystal Water Technology Ltd | Tamworth | 2017 |
| CS Drainage Solutions Limited | Hailsham | 2019 |
| CS Grab Hire Ltd | Abergavenny | 2023 |
| CS HGV & Waste Ltd | London | 2026 |
| CS Skips Ltd | Wakefield | 2020 |
| CSD (Secure Shredding, Destruction & Recycling) Limited | Shrewsbury | 2025 |
| Csebm Limited | Westcliff-On-Sea | 2020 |
| Cser.Tech Limited | London | 2023 |
| CSG Agricultural Limited | Solihull | 2019 |
| CSG Northern Ltd | Dartford | 2017 |
| CSH Environmental Limited | Colchester | 1998 |
| CSL Services Group Ltd | London | 2020 |
| CSR Waste Management Limited | Norwich | 2026 |
| CSS Bradford Ltd | Bradford | 2026 |
| CSS Drainage NW Ltd | Colwyn Bay | 2026 |
| CSS Recycling Ltd | Newbury | 2013 |
| CSW Logistics Limited | Kenilworth | 2014 |
| CT Home Clearance Limited | Waterlooville | 2023 |
| CTC (York) Ltd | Winnersh | 2020 |
| CTD Metals Ltd | Luton | 2022 |
| Ctec (US) Limited | London | 2022 |
| CTK Environmental & Building Services Ltd | London | 2024 |
| CTR Recover Limited | Uttoxeter | 2022 |
| CTS Environmental Services Ltd | Sheffield | 2009 |
| CU Bulk Removals Limited | Cardiff | 2018 |
| Cube (Yorkshire) Ltd | Selby | 2008 |
| Cube Metal Recycling Ltd | Folkestone | 2010 |
| Cube Restoration Limited | Folkestone | 2016 |
| CUE Props CIC | Glasgow | 2021 |
| Culford Waste Limited | Suffolk | 2003 |
| Cullen Beck Recycling Ltd | London | 2024 |
| Cullen Recycling Limited | Dungannon | 2024 |
| Cullen's Clearances Ltd | Wallington | 2012 |
| Culm Valley Recycling Services Limited | Tiverton | 2003 |
| Cumberlow Compost Services Limited | Herts | 2007 |
| Cumbria Waste Management Ltd. | Doncaster | 1991 |
| Cumbria Waste Recycling Limited | Doncaster | 1996 |
| Cuming Containers Ltd | Kingsbridge | 2020 |
| Cunninghame Furniture Recycling Company | Ardrossan | 2010 |
| Cupranaut Limited | Stalybridge | 2012 |
| Curb IT! Limited | Liverpool | 2025 |
| Curley Skip Hire Limited | Thornton Heath | 1994 |
| Curran Drainage Services Limited | Livingston | 2026 |
| Curran Scotland Limited | Livingston | 2025 |
| Curzn Alloys Limited | Stoke-On-Trent | 1997 |
| Cuttle CIC | Leicester | 2026 |
| CV Pallets Limited | Coventry | 2018 |
| CVC Contractors Ltd | Bishop Auckland | 2025 |
| CWB Services (Romford) Limited | Romford | 2020 |
| CWC (NI) Ltd | Antrim | 2012 |
| CWC Services Ltd | Bournemouth | 2020 |
| CWK Waste Transfer Solutions Ltd | Clydebank | 2022 |
| CWM Aggregates Limited | Eastleigh | 2017 |
| CWM Environmental Ltd. | Carmarthen | 1991 |
| CWM Rhondda Waste Management Services Ltd | Cardiff | 2010 |
| CWR Management Ltd | Arundel | 2026 |
| CWS Skip Hire Ltd | Tamworth | 2024 |
| CWS UK Services Ltd | Romsey | 2021 |
| Cwssop Limited | Glasgow | 2025 |
| CYB Environmental Limited | Swanley | 2016 |
| Cycl Limited | Birmingham | 2025 |
| Cycle Link (UK) Limited | London | 2009 |
| Cycle Matter Ltd | Royston | 2025 |
| Cycle Roots CIC | Blackburn | 2013 |
| Cycleflex Europe Limited | London | 2023 |
| Cyclife UK Ltd | Workington | 2003 |
| Cydaf Technologies Ltd | Sutton Coldfield | 2012 |