| Accord Energy Ltd | 2877398 | Millstream, Maidenhead Road, Windsor, SL4 5GD, England |
| Bizzenergy Ltd | 3961223 | BizzEnergy House, Brook Court, Whittington Road, Worcester, WR5 2RX, England |
| British Energy Direct Ltd | 4935015 | Barnett Way, Barnwood, Gloucester, GL4 3RS, England |
| British Gas Trading Ltd (BGAS) | 3078711 | Millstream, Maidenhead Road, Windsor, SL4 5GD, England |
| British Gas Trading Ltd (ENRD) | 3078711 | Millstream, Maidenhead Road, Windsor, SL4 5GD, England |
| Caboodle Energy Ltd | 5159846 | 5 Windsor Court, Clarence Drive, Harrogate, HG1 2PE, England |
| CENTRAL NETWORKS EAST PLC | 2366923 | Westwood Way, Westwood Business Park, Coventry, CV4 8LG, England |
| CENTRAL NETWORKS WEST PLC | 3600574 | Westwood Way, Westwood Business Park, Coventry, CV4 8LG, England |
| Cherwell Energy Ltd | 5199937 | 3 Newbury Street, Wantage, OX12 8BU, England |
| Citigen (London) Ltd | 2427823 | Westwood Way, Westwood Business Park, Coventry, CV4 8LG, England |
| E.ON Energy Ltd | 3407430 | Westwood Way, Westwood Business Park, Coventry, CV4 8LG, England |
| E.ON UK CHP Plc | 2684288 | Westwood Way, Westwood Business Park, Coventry, CV4 8LG, England |
| E.ON UK Plc | 2366970 | Westwood Way, Westwood Business Park, Coventry, CV4 8LG, England |
| Economy Power Ltd | 3385578 | Westwood Way, Westwood Business Park, Coventry, CV4 8LG, England |
| EDF Energy Customers Plc | 2228297 | 40 Grosvenor Place, Victoria, London, SW1X 7AW, England |
| EDF ENERGY NETWORKS (EPN) PLC | 2366906 | 40 Grosvenor Place, Victoria, London, SW1X 7EN, England |
| EDF ENERGY NETWORKS (LPN) PLC | 3929195 | 40 Grosvenor Place, Victoria, London, SW1X 7EN, England |
| EDF ENERGY NETWORKS (SPN) PLC | 3043097 | 40 Grosvenor Place, Victoria, London, SW1X 7EN, England |
| Electricity 4 Business Ltd | 5064028 | 3 Radian Court, Knowlhill, Milton Keynes, MK5 8PJ, England |
| Electricity Direct (UK) Ltd | 3174056 | Millstream, Maidenhead Road, Windsor, SL4 5GD, England |
| Electricity North West Limited | 2366949 | Dalton House, 104 Dalton Avenue, Birchwood, Birchwood Park, Warrington, WA3 6YF, England |
| Electricity Plus Supply Limited | 5199936 | Dryden House, The Edge Business Centre, Hunber Road, London, NW2 6EW, England |
| Energetics Electricity Ltd | SC234694 | Silverwells House, 114 Cadzow Street, Hamilton, ML3 6HP, England |
| Energy COOP Ltd | 6053905 | Tower House, Parkstone Rd, POOLE, BH15 2JH, England |
| Energy Data Company Limited | 4741972 | Hurst House, 131-133 New London Road, Chelmsford, CM2 0QT, England |
| Energyco2 Ltd | 5095555 | 3 Radian Court, Knowlhill, Milton Keynes, MK5 8PJ, England |
| ESP Electricity Limited. | 4718806 | Hazeldean, Station Road, Admirals Park, Leatherhead, Surrey, KT22 7AA, England |
| First Utility Limited | 5070887 | 19 South Audley Street, London, W1K 2NU, England |
| Gaz De France Marketing Ltd | 4236804 | 1 City Walk, Leeds, LS11 9DX, England |
| Good Energy Ltd | 3899612 | 2 Temple Back East, Temple Quay, Bristol, BS1 6EG, England |