| Indaver IWS Cheshire Limited | Middlewich | 2012 |
| Indaver Ness Services Limited | Aberdeen | 2019 |
| Indaver Rivenhall Holdings Limited | Kelvedon | 2020 |
| Indaver Rivenhall Limited | Kelvedon | 2020 |
| Indaver UK Limited | Middlewich | 2007 |
| Independent Asbestos Consultants Ltd | Buckie | 2020 |
| Independent Restoration Limited | Prudhoe | 2014 |
| Independent Scrap Co. Limited | Loughton | 2003 |
| Independent Water Networks Limited | Bury St. Edmunds | 2006 |
| Index Waste Management Ltd | Romford | 2026 |
| Indigo UK Trading Ltd | Rotherham | 2020 |
| Indigo Water Limited | Reading | 2024 |
| Indivus (Scotland) Ltd | Mauchline | 2023 |
| Indonere Limited | Ruislip London | 2026 |
| Indratec Ltd | Battle | 2023 |
| Industrial Asbestos Services Limited | Wigan | 2015 |
| Industrial Cleaning & Green Solutions Limited | Nottingham | 2025 |
| Industrial Contractors Limited | Bromsgrove | 1982 |
| Industrial Decontamination Services (UK) Ltd | Chorley | 2026 |
| Industrial Phycology Limited | Worcester | 2012 |
| Industrial Reclamation and Salvage Limited | Chorley | 2002 |
| Industrial Recycling Machinery Limited | Spilsby | 2009 |
| Industrial Rentals Limited | Dunoon | 2014 |
| Industrial Treatment Services Ltd | Ormskirk | 1976 |
| Industrial Waste Recycling Ltd | Crawley | 2013 |
| Industrial Wastewater Services Ltd | Chester | 2021 |
| Industrial Water Equipment Limited | Matlock | 2007 |
| Industrial Water Jetting Systems Group Limited | Bromsgrove | 2010 |
| Industrial Water Jetting Systems Limited | Manchester Road | 1977 |
| Industrial Water Solutions Ltd | London | 2019 |
| Inert Landfill & Restoration Management Limited | Eastleigh | 2020 |
| Inert Recycling (Sussex) Limited | Eastleigh | 2024 |
| Inert Recycling (UK) Limited | Eastleigh | 1999 |
| Inertech Waste Consultancy Limited | Southampton | 2013 |
| Inerto Ltd | Preston | 2018 |
| Inferno Trading Limited | Cardiff | 2023 |
| Infinite Alchemy Ltd | Maidstone | 2022 |
| Infinite Recycling Limited | Wolverhampton | 2025 |
| Infinite Textile (UK) Ltd | Leicester | 2014 |
| Infinite Waste Management Ltd | Bristol | 2022 |
| Infinity Drainage Solutions Ltd | London | 2019 |
| Infinity Environmental Solutions Limited | Guisborough | 2014 |
| Infinity SRL Ltd | Chadwell Heath | 2026 |
| Infinity Trade Network Limited | London | 2025 |
| Inflecta Group Limited | London | 2026 |
| Info Revolution Limited | Manchester | 2010 |
| Ingfield Lane Pumping Station Limited | Settle | 2006 |
| Inglemere Metals (Blackpool) Limited | Poulton-Le-Fylde | 2016 |
| Ings Environmental Limited | Pontefract | 2011 |
| Iniperor Limited | London | 2025 |
| Inish Haulage Ltd | Greenford | 2022 |
| INK and Toner Recycling Ltd | Milton Keynes | 2012 |
| Inkviro Limited | Letchworth Garden City | 2007 |
| Inline Drainage Solutions Limited | Sleaford | 2015 |
| Inneauvate Limited | London | 2022 |
| Inner City Environmental Ltd | Dartford | 2006 |
| Inner City Waste Management Ltd | Brentwood | 2017 |
| Innercitywaste Limited | London | 2022 |
| Innocap UK Limited | Belfast | 2023 |
| INNOV8 UK Group Limited | London | 2023 |
| Innovagen Limited | Cheltenham | 2017 |
| Innovation Waste Services Ltd | Rotherham | 2025 |
| Innovative ASH Solutions Ltd | Paisley | 2019 |
| Innovative Environmental Services Ltd. | Falkirk | 2003 |
| Innoveau Solutions Limited | Marston Moreteyne | 2012 |
| Innovo Vdq-Nrg WASTE2VALUE SPV Number 1 Limited | Thatcham | 2025 |
| Innowaste Ltd | Birmingham | 2025 |
| Innox Waste and Recycling Limited | Maidstone | 2020 |
| Innskips Ltd | Church Village | 2023 |
| Inove Intl Limited | Manchester | 2009 |
| Inret-Consulting Ltd | Cardiff | 2019 |
| Insect Armour Ltd | Leeds | 2021 |
| Inside OUT Environmental Limited | Lichfield | 2007 |
| Insima Waste Management Ltd | Brixworth | 2026 |
| Insitu FM Ltd | Dunstable | 2014 |
| Inspect-A-Drain (Midlands) Limited | Coalville | 2017 |
| Inspecton Limited | Bolton | 2014 |
| Inspire Waste Management Ltd | Gateshead | 2016 |
| Insta Waste Solutions Limited | Nottingham | 2010 |
| Instaclear Ltd | London | 2022 |
| Install Integrated Skips Limited | Barry | 2016 |
| Install Recycling Limited | Plymouth | 2024 |
| Install Waste Management Ltd | Barry | 2016 |
| Instant Drains Limited | Ongar | 2014 |
| Instant Rubish & Waste Clearance Ltd | Croydon | 2016 |
| Insul-Eight Environmental Limited | Preston | 2012 |
| Insulation Extraction Specialists Ltd | Ebbw Vale | 2015 |
| Intact Solutions Ltd | Burnopfield | 1998 |
| Intake Motors Global Ltd | Sheffield | 2025 |
| Intec Future Solutions Ltd | Ipswich | 2020 |
| Integral Flow Ltd | Rochester | 2020 |
| Integrated Flexi Solutions Ltd | Sheffield | 2016 |
| Integrated Waste Management Limited | Doncaster | 1989 |
| Integrated Water Services Limited | Walsall | 2004 |
| Integrum Vehicle Solutions Limited | Glasgow | 2016 |
| Intelligent Business Water Ltd | Coatbridge | 2021 |
| Intelligent Drainage Solutions Limited | Retford | 2013 |
| Intelligent Metal Solutions Limited | Rotherham | 2014 |
| Intelligent Renewables Ltd | London | 2016 |
| Intelligent Waste Solutions Limited | Ilkley | 2019 |