Government initiatives in support of Gatwick's development also included new policies to transfer all scheduled services between London and Canada as well as London and the Iberian peninsula from Heathrow to Gatwick by 1 April 1979, banning whole-plane charters at Heathrow and to compel all airlines that were planning to operate a scheduled service to or from London for the first time to use Gatwick instead of Heathrow. The latter policy was officially known as the "London Traffic Distribution Rules". It came into effect on 1 April 1978 and was applied retroactively from the beginning of April 1977. These rules were designed to achieve a fairer distribution of traffic between London Heathrow and London Gatwick, the UK's two main international gateway airports. The policy was aimed at increasing Gatwick's utilisation to help the airport make a profit.