In October 1974, 111 Squadron converted from the Lightning to the Phantom FGR.2, becoming the first unit to operate the type in the air defence role (notwithstanding 43 Squadron, which had used the FG.1 version since 1969). As more Jaguars were delivered, Phantoms were released enabling existing Lightning squadrons to be converted; 19 Squadron and 92 Squadron, the forward deployed air defence units in Germany, converted in 1976 and 1977 respectively, at the same time moving from RAF Gütersloh, which was the closest RAF base to the East German border, to RAF Wildenrath, taking advantage of the Phantom's superior range over the Lightning. Three further UK based squadrons, 23, 29 and 56, were also converted between 1974 and 1976. 111 Squadron, which had been the first unit to use the FGR.2 as an interceptor, converted to the FG.1 version in 1979 following the transfer of the RN's remaining airframes to the RAF. The Phantom subsequently served as the RAF's primary interceptor for over a decade until the introduction into service of the Panavia Tornado F.3 in 1987.