It was a relatively large missile, which limited it to stationary defensive roles similar to the Hercules or the Soviets' S-25 Berkut, although Sweden operated its Bloodhounds in a semi-mobile form.

The two missiles served in tandem for some time, until the shorter-range role of the Thunderbird was replaced by the much smaller and fast-acting BAC Rapier starting in 1971.

The Royal Navy was primarily interested in weapons to counteract Luftwaffe bombers dropping glide bombs, which had been used with great effectiveness during the invasion of Italy, and looking toward countering the kamikaze threat in the Pacific.

The GAP team suggested combining the Navy's new Type 909 radar with a new missile to produce a Brakemine-like system but with considerably higher accuracy and much longer range.

They took over LOPGAP development from the Navy, as well as using up most existing Stooge and Brakemine systems to gain familiarity with the needs of missile testing.

Around the same time, the Army began to express doubts about the Red Heathen as it became clear that the beam riding guidance systems of the early experimental missiles did not work at long range.

The Cherry Report called for a reorganisation of existing radars under the ROTOR project along with new control centres to better coordinate fighters and anti-aircraft guns.

This was strictly a stop-gap measure however; over the longer term there would be a requirement for deployment of new long-range radars in place of the Chain Home systems from the war, construction of command and control sites able to survive a nuclear attack, interceptors of ever-increasing performance, and anti-aircraft missiles and guns to provide a last-ditch defence.

As the ramjet only operates effectively at high speeds over Mach 1, Bristol built a series of testbed airframes to flight-test the engines.

Early problems were ironed out and the JTV series was the first British ramjet powered aircraft to operate continually at supersonic speeds.

The intake and wings give it some resemblance to the English Electric Lightning, albeit with a long tube sticking out of the aft end.

A second design was similar, but used mid-mounted fins of reverse-delta shape (flat at the front) with small intakes at their roots.

Bristol was concerned that the angles needed to generate the required lift using this method would be too great for the engines intakes to deal with, so it adopted the twist and steer system, first experimented with on the war-era Brakemine project.

This kept airflow in the direction of the missile body, and thus the engine intakes, as well as greatly reducing the drag caused by the tilting of the fuselage across the relative wind.

The long, thin fuselage offered very low rotational inertia, conferring excellent homing performance in the last few seconds.

[8] In the initial designs, a single very large solid fuel booster launched the missile off its launcher and powered it to speeds where the ramjets could take over.

The final modification, first tested on the XTV-3, was to replace the four rear fins with two larger ones, which allowed the four booster motors to be mounted on a common ring, ensuring they separated in different directions.

The resulting Bristol Thor was originally designed in conjunction with Boeing, which had extensive experience with the similar engines of the BOMARC missile.

Testing of the prototype production versions, known as XRD (eXperimental Red Duster), moved to the Woomera range in South Australia in mid-1953.

This was handled by the truck-mounted Type 83 "Yellow River" pulse radar system that could be fairly easily jammed and was vulnerable to ground "clutter", thus degrading low-level capability.

The Bloodhound Mk 1 entered British service in 1958, and was selected for the Royal Australian Air Force (RAAF) in November of that year.

[10] By 1955 it appeared that the Stage 2 missile, originally known as Green Sparkler but now as Blue Envoy, was too far beyond the state of the art to be able to enter service before the Thunderbird and Bloodhound became obsolete.

The Paper argued that the Soviets would move their strategic forces to ballistic missiles and that the likelihood of an air attack solely by bombers would be increasingly unlikely.

Bristol engineers sharing a taxi with their Ferranti counterparts hatched a new plan to adopt the Blue Envoy ramjets and radars to a lengthened Bloodhound, and submitted this for study.

The main missile is a long cylinder of magnesium frames and aluminium alloy skin with a prominent ogive nose cone at the front and some boat-tailing at the rear.

In action, they fold open like the petals on a flower, greatly increasing drag and pulling the entire four-booster assembly away from the missile body.

[16][17] Small inlets on the roots of the stub wings holding the engines allow air into the missile body for two tasks.

Two ram air turbines driving turbopumps generate hydraulic power for the wing control system, and a fuel pump that feeds the engines.

[9] Although in tests the Bloodhound had executed direct hits on target bombers flying at 50,000 feet (15,000 m),[18] Mark II production models, in common with many air-to-air and surface-to-air missiles of that period and after, had a proximity fuzed continuous rod warhead (known as the K11A1) designed to destroy attacking aircraft without requiring a direct hit.

Three seconds after launch, as the four boost rockets fall away, it has reached Mach 2.5 which is roughly 1,800 mph" The planned Mk III (also known as RO 166) was a Mark II with 6 kiloton nuclear warhead and a range of around 125 mi (201 km) achieved with an improved ramjet engine and bigger boosters.