| Ian's Bees Limited | Wareham | 2023 |
| Ibbotsons Limited | York | 2017 |
| Ibec Limited | Kettering | 2000 |
| Ibex Capital Solutions Ltd | Gerrards Cross | 2012 |
| IBN EL Khadra Ltd | London | 2025 |
| IC Joseph Limited | Hereford | 2007 |
| ICB Garden Maintenance Ltd | Canterbury | 2019 |
| ICD Contracting Ltd | Oban | 2010 |
| Ice Equestrian Ltd | Galashiels | 2020 |
| Iceberg (Eco) Ltd | Derby | 2021 |
| Iceni Anglia Limited | Norwich | 1979 |
| Iceni Tree Care Ltd | King'S Lynn | 2019 |
| Ichiwawa Ltd | London | 2022 |
| Icid Limited | Andover | 1993 |
| Icke Partners Limited | Pershore | 2018 |
| Ickjou Limited | Cardiff | 2023 |
| ICM Sustainable Solutions Limited | Thetford | 2015 |
| Iconicsx Limited | Edinburgh | 2024 |
| ICP Partners Europe Limited | Cardiff | 2004 |
| ID & GC Howard Limited | Huntingdon | 2006 |
| ID & Trace Limited | Halesworth | 2011 |
| IDA Farm Ltd | Lytham St. Annes | 2024 |
| Ideafruit UK Limited | Faversham | 2016 |
| Ideal Breeding Ltd | Darlington | 2022 |
| Ideal Pet Foods Limited | Liskeard | 2014 |
| Ideal Seafoods Limited | Liskeard | 2016 |
| Ideka Ltd | London | 2018 |
| Identify Analytic Data Information Juridic Justice Ltd | Brentwood | 2025 |
| Idesign Ossett Kennels Limited | Ossett | 2025 |
| Idfm: Animal Services Ltd | Canning Town | 2024 |
| Idgas Enterprises Ltd | London | 2024 |
| Idle Farm Ltd | Kettleshulme | 2024 |
| Idle, Torne and Trent Water Abstractors Group CIC | Mansfield | 2026 |
| Idnat Holdings Ltd | Reading | 2023 |
| Idris Stables Limited | Newport | 2023 |
| IDS Industries Limited | St. Leonards-On-Sea | 2024 |
| Iduna Lifestyle Limited | Epping | 2023 |
| Idvies Farms Limited | Forfar | 2001 |
| IE & TM Speed Limited | Northwich | 2008 |
| IEC Beef Limited | Market Drayton | 2018 |
| IEC Poultry Limited | Market Drayton | 2018 |
| IED Solutions Ltd | Uttoxeter | 2007 |
| IF & CA Nicolson Limited | Shetland | 1996 |
| Ifagri Ltd | London | 2017 |
| IFH Ventures Limited | Isle Of Islay | 2020 |
| IFI Group Holding Company Ltd | Lincoln | 2024 |
| Ifield Botanics UK Ltd | Westcliff-On-Sea | 2022 |
| Ifjac's Limited | Beaminster | 2017 |
| IFM Broxtead Ltd. | Newmarket | 2025 |
| Iford Downs Shoot Ltd | Spalding | 2010 |
| Iford Shoot Ltd | Spalding | 2014 |
| IFS Equestrian Ltd | Wittersham | 2022 |
| IFT Services Limited | Mansfield | 2000 |
| IFW Limited | Manchester | 2000 |
| IG Fisheries Limited | Nottingham | 2009 |
| Igale Investment Group Limited | London | 2025 |
| IGB Trading Limited | London | 2014 |
| IGK Farming Limited | Killin | 2013 |
| Ignuf Ltd | London | 2024 |
| IGS Services (Whalsay) Limited | Shetland | 2019 |
| Ihbss Limited | Poole | 2013 |
| IJ Agricultural Fencing Services Ltd | Newbury | 2011 |
| IJ and CJ Talbot Ltd | South Brent | 2017 |
| Ijim Consulting Ltd | London | 2019 |
| IJM Shellfish Ltd | Aberdeen | 2023 |
| IJR Lighting Ltd | Church View | 2019 |
| IJS Contracting Ltd | Gloucester | 2024 |
| IKE Marine Limited | Brixham | 2022 |
| IKH Farms Limited | Nantwich | 2014 |
| Iknc Ltd | Buckie | 2022 |
| Ikon Deerstalking Ltd | Christchurch | 2020 |
| Ilchester Farms Ohio Limited | Dorchester | 2014 |
| Ileaf Systems Limited | Leeds | 2021 |
| Ileden Shoot Limited | Sittingbourne | 2021 |
| Ilene Limited | Newry | 2005 |
| Iles Forestry Limited | Hartlepool | 2018 |
| Ilex Envirosciences Limited | Atherstone | 2003 |
| Ilex Replanted Forestry Limited | Hull | 1998 |
| Ilexalex Ltd | Exeter | 2025 |
| Iley Foals Ltd | Preston | 2019 |
| Ilfracombe Dive and Fishing Charters Ltd | Barnstaple | 2015 |
| Ilion Property Ltd | Windsor | 2025 |
| Illsley (Chieveley) Limited | Newbury | 1957 |
| Illuminance Ltd | Eastleigh | 2023 |
| Illustrious Fishing Ltd. | Kirkwall | 2014 |
| Ilmington Farm Limited | Wimborne | 2023 |
| IM Green Care Limited | Rotherham | 2026 |
| Imaginative Creation Limited | Nottingham | 2025 |
| Imagine LAB Education Ltd | Wolverhampton | 2023 |
| Imago Fishing Limited | Aberlour | 2011 |
| Imal Trading Limited | Liverpool | 2013 |
| Imberhorne Lane Nursery Plant Centre Ltd | East Grinstead | 2018 |
| IMJ Dairy Ltd | Bala | 2020 |
| Imladris Smallholding Ltd | Lampeter | 2025 |
| Immature Garden Ltd | Hertford | 2019 |
| Immediate Action : Tactical Options Limited | Pontyberum | 2005 |
| Immunall Limited | King'S Lynn | 2001 |
| Imogen Fishing Ltd | St Columb | 2021 |
| Imoherbs Ltd | Dagenham | 2025 |
| Imon Site Ltd | Norfolk | 2002 |