| Clearsolve Ltd | Milton Keynes | 2025 |
| Clearspace Recycling Limited | Frome | 2024 |
| Clearspace Rubbish & Recycling Limited | Glasgow | 2025 |
| Clearstone Property Services Ltd | Nuneaton | 2026 |
| Clearteam Ltd | Birmingham | 2026 |
| Cleartech Group Holdings Ltd | Glasgow | 2025 |
| Cleartech Group Ltd | Glasgow | 2004 |
| Cleartech Water Services Limited | Urmston | 2008 |
| Clearvac International Limited | Exeter | 2009 |
| Clearvac Offshore Limited | Exeter | 2021 |
| Clearvale Solutions Ltd | Ramsgate | 2025 |
| Clearview Drainage Ltd | Milton Keynes | 2025 |
| Clearwater D C 2001 Limited | Glasgow | 2002 |
| Clearwater Designs Limited | Birmingham | 1990 |
| Clearwater Pools (UK) Limited | Birkenhead | 2006 |
| Clearwater Scenery Limited | Gravesend | 2002 |
| Clearway Clearances Limited | Greenford | 2021 |
| Clearway Disposals Limited | Co.Armagh | 1981 |
| Clearway Haulage & Removals Ltd | Bonnyrigg | 2026 |
| Clearway Holdings Limited | Craigavon | 2005 |
| Clearway Operations Ltd | Bradford | 2025 |
| Clearway Plumbing & Drains Ltd | Beaconsfield | 2015 |
| Clearway Property Group Limited | Luton | 2026 |
| Clearway Recycling Services Ltd | Manchester | 2025 |
| Clearway Waste Removal Ltd | High Wycombe | 2024 |
| Clearway Waste Services Ltd | Manchester | 2026 |
| Clearways Environmental Ltd | Bexhill On Sea | 2024 |
| Clearways Group Limited | Halstead | 2026 |
| Clearwise Newbury Limited | Newbury | 2009 |
| Clearwise Treatment Services Limited | Newbury | 2025 |
| Clee Hill Common Conservation Limited | Ludlow | 1996 |
| Clee Metals Limited | Grimsby | 2012 |
| Cleenwater Limited | Bexhill | 2006 |
| Clement Waste Management Limited | Swansea | 2023 |
| Clemson Grab Hire Ltd | Lichfield | 2026 |
| Clevedon Court Management Company Limited | Ashford | 1995 |
| Cleveland Auto Recyclers Limited | Saltburn | 2003 |
| Cleveland Waste Paper Limited | Hartlepool | 2003 |
| Clever Recycling Ltd | Bury | 2020 |
| Clever Works Ltd | London | 2022 |
| Cleverclear Limited | Knutsford | 2020 |
| Clews Recycling Ltd | Rugby | 1999 |
| CLG Enviro Ltd | Dungannon | 2025 |
| Click & Clear Rubbish Removal Ltd | Mansfield | 2020 |
| Click a Skip Nationwide Limited | Farnham | 2014 |
| Click and Clear Waste Solutions Ltd | Mansfield | 2019 |
| Click Clear Group Limited | Sevenoaks | 2024 |
| Click Clear Ltd | Mitcham | 2023 |
| Click Group Services Ltd | Covent Garden | 2025 |
| Click Van Ltd | London | 2026 |
| CLICK2COLLECT Ltd | London | 2025 |
| Cliffeville Limited | Maidenhead | 1980 |
| Clifford's WM Limited | Chelmsford | 2003 |
| Clifft Waste Management Ltd | Wolverhampton | 2026 |
| Climate Earth Solutions Livestock Ltd | London | 2026 |
| Climate Earth Solutions Ltd | Manchester | 2024 |
| Climate Hebrides CIC | Stornoway | 2022 |
| Climeworks UK Ltd | London | 2023 |
| Clinical Waste Solutions Limited | Ferndown Industrial Estate | 2002 |
| Clinipower Limited | Bristol | 2012 |
| Clinitek Energy Ltd | Manchester | 2025 |
| Cliniwaste Health South Limited | Glasgow | 2019 |
| Clinix Transport Solutions Ltd | Aldershot | 2025 |
| Clive Smith Skip Hire Limited | Dorchester | 2003 |
| CLM Waste Management Ltd | Brentwood | 2021 |
| Cloacina Services Limited | Cheltenham | 2020 |
| Clockhouse 3 Limited | London | 1952 |
| Clockwork Limited | Dorchester | 1995 |
| Clog Away Ltd | Bootle | 2026 |
| Close the Loop (Europe) Limited | London | 2005 |
| Closed Loop IOW Ltd | Cowes | 2026 |
| Clothes Collections Ltd | Birmingham | 2017 |
| Clothes Line Rags Ltd | Nottingham | 2018 |
| Clothes Recycling UK Ltd | Milton Keynes | 2021 |
| Clothing Export Limited | Newry | 2011 |
| Clout Resources Limited | Birmingham | 2015 |
| Clover Environmental Services Limited | Southend-On-Sea | 2020 |
| Clover Equipment UK Ltd | Birmingham | 2014 |
| Clover Truck and Plant Hire Limited | Liverpool | 2020 |
| Cloverleaf Acquisitions Limited | Wilmslow | 2025 |
| Cloverleaf Aluminium Limited | London | 2025 |
| Cloverleaf Metals Limited | Wilmslow | 2025 |
| Clutter Clear Ltd | Caerphilly | 2024 |
| CLUTTER2CLEAR Ltd | Hertford | 2018 |
| CLW Building Maintenance Ltd | Warrington | 2023 |
| Clyde Metal Recycling Ltd. | Renfrewshire | 1998 |
| Clyde Valley Recycling Ltd | Glasgow | 2025 |
| Clyde Waste Solutions Limited | Glasgow | 2023 |
| Clyffe Sewerage Management Limited | Dorchester | 2014 |
| CM Demolition Ltd | Peterborough | 2022 |
| CM Pumps Ltd | Dartford | 2025 |
| CM Recovery Limited | Craigavon | 2025 |
| CM Recycling Services Ltd | Stafford | 2024 |
| CM Shelfco (4) Limited | Milton Keynes | 2025 |
| CM Skips (Coleraine) Limited | Antrim | 2021 |
| CM Skips Limited | Belfast | 2014 |
| CM Waste Collections Wales Ltd | Cwmbran | 2024 |
| CM Waste Services Limited | Ballyclare | 2020 |
| Cmec 4 Limited | Dunkirk | 2014 |
| Cmec 4 Skips Limited | Nottingham | 2022 |