carrier at that time). Following the merger, most of the fleet progressively adopted Air UK's new blue, white and red colour scheme. Originally, this featured a predominantly blue fuselage with a white-red-white strip across the windows and a white roof. The tail was also predominantly blue, apart from the "Air UK" logo. However, the Civil Aviation Authority (CAA) disapproved of this predominantly blue livery, arguing that it could potentially pose a safety hazard for other aircraft as it was difficult for other crews to see the blue aircraft against a blue sky. To address the CAA's safety concerns, Air UK decided to amend its original colour scheme by opting for a hybrid blue-and-white scheme featuring a blue fuselage and a white tail. Air UK's scheduled route network initially served the following 33 points: Aberdeen, Amsterdam, Basel, Belfast, Bergen, Birmingham, Blackpool, Bournemouth, Brussels, Dublin, Düsseldorf, Edinburgh, Exeter, Glasgow, Guernsey, Humberside, Isle of Man, Jersey, Leeds/Bradford, Le Touquet, London Gatwick, London Heathrow, London Stansted, Manchester, Newcastle, Norwich, Ostend, Paris, Rotterdam, Southampton, Southend, Stavanger, and Teesside. Air UK was the first and, at the time, only scheduled airline in the UK to fly from all three main London airports. Following British Airways' decision to retire its Vickers Viscount turboprop fleet and to withdraw from its loss-making regional scheduled routes, Air UK assumed BA's regional routes from Heathrow to Guernsey, Manchester to the Isle of Man, Leeds to Belfast and Dublin, and Edinburgh to Jersey in April 1980. Air UK's new, year-round Heathrow—Guernsey route was its most prominent scheduled route serving London's premier airport. (During the late 1970s, in the days prior to the construction of the M11, Air UK's predecessor Air Anglia had launched a year-round scheduled service linking Heathrow with the company's bases in Norwich and Humberside, as well as a year-round scheduled operation between London Gatwick and Leeds.) Retrenchment The severe recession of the early 1980s necessitated a major retrenchment, resulting in extensive frequency, route and staff cutbacks. This entailed the closure of bases at Bournemouth, Humberside and Stansted as well as a major reduction in operations at Southend. As a consequence of these cutbacks, ten turboprop aircraft (seven Heralds and three Bandeirantes) were withdrawn from service while the two F-28 jets were leased out to French regional carrier Air Alsace. This in turn resulted in the closure of the former BIA engineering base at Blackpool, accounting for 220 out of