This article is a summary of a number of papers presented at an IEE Colloquium in Glasgow on the upgrading of the interconnection between Scotland and England. The work involved Scottish Power, Scottish Hydro-Electric and National Grid Company in a multi-discipline project which, from authorisation to commissioning took 34 months, with a total investment of 125 Pounds million from the Scottish companies. The capacity of the interconnector has been increased from 850 MW to 1600 MW and this has been achieved by the integration of several complementary developments, ＇including the construction of the longest transmission line to be built in the UK in 25 years (125km), three new substations, two static VAr compensators (SVCs) and modifications to the excitation and automatic voltage regulators (AVRs) at three Scottish power stations.