The third production F-4K, or Phantom FG.1 as it was designated in FAA service, XT859 made its first flight in the USA on January 1, 1968, and was delivered to Intensive Flying Trials Unit No 700P Sqn at RNAS Yeovilton wearing the codes “725/VL” on May 21 the same year.

The Phantom FG.1 air-defence interceptor variant entered RAF service with No 43 Sqn at Leuchars in September 1969. This example, XV574, wears the unit’s distinctive chequerboard marking around the roundel and its “Fighting Cocks” fin badge.

With both Spey afterburners roaring and the double-length nosewheel oleo fitted to the FAA’s examples fully extended for a catapult launch, Phantom FG.1 XV591 of No 892 Sqn prepares to depart HMS Ark Royal.

Streaming vortices from the wingtips and with full afterburner applied, XT868 “153/VL” of No 767 Sqn makes a noisy departure from Yeovilton in 1969. The open auxiliary air door in the fuselage forward of the exhaust was fitted only to Spey-powered Phantoms and automatically opened at air speeds below 210kt to aid airflow.

Showing the F-4K’s distinctive extended nosewheel oleo to good effect (fitted to provide an increased angle of attack for use from British carriers, which were smaller than their American counterparts), second production example XT858 is seen here undergoing jet-blast-deflector trials at the Royal Aircraft Establishment at Bedford in May 1968.

With wingtip vortices trailing, two 56 Sqn Phantom FGR.2s bank over the North York Moors

Phantom FG.1 XT859 of Royal Navy trials unit No 700P Sqn is run up to full power before taking off to perform a blistering routine at an air display in October 1968. A number of the unit’s Phantoms had their fins emblazoned with a red-orange diamond containing McDonnell technical artist Tony Wong’s "Spook" caricature.

The RAF initially used the Phantom in two distinct roles; the FG.1 was a dedicated air-defence interceptor and the FGR.2 was tasked with the ground-attack and tactical reconnaissance roles. This FGR.2, XV394, is seen here in January 1969 at RAF Coningsby, where it operated with No 228 Operational Conversion Unit.

The first supersonic Spey is prepared for air freighting at Rolls-Royce’s Derby factory in November 1965, for shipping to the USA to become one of the pair fitted to XT595, the first of the Royal Navy’s two YF-4K prototypes; XT595 made its first flight at St Louis on June 17, 1966, followed by the second YF-4K, XT596, on August 30.

Designed by a team led by Frederick Morley, the Rolls-Royce RB.163 Spey was a neat two-spool low-bypass turbofan, and was modified into the RB.168 “supersonic Spey” with afterburner for military applications, an example of which is seen here. The Spey was of greater diameter than the American J79, and extensive modifications had to be made to the F-4K and -M to accommodate it.

When the Hawker Siddeley P.1154 was cancelled in February 1965, the RAF followed the Royal Navy’s lead and also selected the Phantom, the RAF version being designated F-4M by McDonnell. The first of the two YF-4M prototypes, XT852, is seen here on the ramp at McDonnell’s St Louis factory; it first flew on February 17, 1967.