EXHIBIT 21.1 SIUK plc - subsidiaries % SIUK plc Subsidiary owned Status - ---------------------------------------------------- ----- --------- South Western Electricity plc 100 Operating @ebusiness Limited 100 Dormant Aztec Insurance Limited 100 Operating EA Technology Limited 7.7 Operating ElectraLink Limited 6.19 Operating Electricity Association Limited 5.9 Operating Electricity Pensions Limited 0 Operating Electricity Pensions Trustee Limited 5 Operating ESN Holdings Limited 4.5 Operating Meter Reading Services Limited 100 Operating Non-Fossil Purchasing Agency Limited 8.3 Operating Northmere Limited 0 Operating REC Collect Limited 25 Operating South West Enterprise Limited 0 Operating South Western Helicopters Limited 100 Operating St Clements Services Limited 9.1 Operating Western Energy Limited 100 Dormant Western Power Generation Limited 100 Operating Western Power Investments Limited 100 Operating Teesside Power Limited 7.7 Operating Wind Resources Limited 45 Operating Carland Cross Limited 100 Operating Coal Clough Limited 100 Operating Western Power Networks Limited 100 Dormant Western Power Pension Trustee Limited 100 Dormant Western Power Training Limited 100 Dormant WPD Energy Limited 100 Dormant WPD Helicopter Unit Limited 100 Dormant WPD Insurance Limited 100 Operating WPD Investments Limited 100 Operating Croeso Systems Development Limited 50 Operating ebusiness South West Limited 90 Operating Avonbank Limited 100 Dormant WPD Meter Operator Services Limited 100 Dormant WPD Property Developments Limited 100 Operating Temple Back Developments Limited 100 Operating Weston-Super-Mare Developments Limited 100 Operating WPD Property Investments Limited 100 Operating WPD Share Scheme Trustees Limited 100 Dormant WPD Telecoms Limited 100 Dormant SIUK Capital Trust I 100 Operating Surf Telecoms Limited 100 Operating Western Power Distribution Telecoms Limited 100 Operating