By the early 1980s, the traditional regional structure of British rail was increasingly outdated and, in 1982, the passenger business was split into three sectors: InterCity, London & South East and provincial. For the first time in railway history, all of the main-line services operating into the London termini along with the rest of the railways in southeast England were united into a single and co-ordinated structure. In 1986, following the appointment of Chris Green as Chairman, the London & South East sector was rebranded as Network SouthEast with a new and bright livery of red, white and blue. With the area of operation extended to include King's Lynn and Exeter, there was to be almost a decade of major investment in new rolling stock, infrastructure and marketing that was to see NSE as one of the most innovative of railway operators.
NSE-branded locomotives operated on services from Waterloo to Exeter, from Paddington over the GWR main line and over the ex-GER lines of East Anglia, whilst major investment saw electrification to Norwich and the reopening of the Snow Hill tunnel, permitting the creation of the electrified service from the ex-Midland main line through to the former Southern Region. New units arrived in large numbers, revolutionising services, for example, into London Marylebone.