It was originally created in 1947 as the nationalised Merseyside and North Wales Electricity Board in the Electricity Act 1947 but was privatised in 1990 to become Manweb plc.
It was purchased by Scottish Power in 1995, and subsequently become SP Manweb plc. The Manweb name continued to be used alongside the Scottish Power logo on home and retail publications up until mid-2007, when it was replaced by "ScottishPower". However, the Merseyside, Cheshire and North Wales electricity distributor continues as SP Manweb plc, which is managed along with the Scottish transmission operators SP Distribution plc and SP Transmission plc as SP Energy Networks. A fourth company, SP Power Systems Ltd maintains the distribution networks for these each of these companies.