Replacing the earlier generation of much heavier nuclear air-launched bombs, Hunting Engineering at Luton developed and built in the early sixties a suitable nuclear weapon that could be launched by relatively small aircraft instead of with the much larger V-bombers. It was specially developed to be carried by the Blackburn Buccaneer and B.A.C. TSR-2 tactical attack bombers. When the TSR-2 was cancelled the Tornado was later also used as an alternative. Loaded with weapons-grade Uranium235 the bomb had a maximum yield of some 10 kiloton TNT. Basically this was more than sufficient for the total destruction of its main targets: large enemy vessels, complete harbour installations, military production facilities and large military bases. Designated as ‘WE177A’ it became operational in the U.K. by 1966.

The WE177A was basically a streamlined casing with four small stabilizing fins fitted with its nuclear load with the following characteristics:

The estimated number of bombs manufactured is 107. It was armed before the start of a nuclear mission with two special keys. It had a pre-determined setting for detonation at 40 m and after launch it was slowed down with a small parachute. The Buccaneer used a standard LABS or toss bombing technique where the weapon was released at full speed on the top of a climb. From here it followed a ballistic trajectory to its target. After release the Buccaneer made a half-loop and a roll to fly away as fast as possible into the opposite direction of the detonation point. The WE177A was operational until 1992. A somewhat larger and heavier version carrying a 450 KT thermonuclear load was known as the WE177B. It was a typical weapon for strategic use by the V-bombers.