The WE177 was the last air-launched atomic bomb in the inventory of the United Kingdom. It was a free-fall thermonuclear weapon which became operational in late 1966, replacing the Red Beard. It was also used as a nuclear depth charge by Royal Navy vessels. WE 177 was produced in three models:

• Type A weighed 272 kg (600 lb), with a yield of 200 kT. This was a fission bomb.

• Type B weighed 431 kg (950 lb), with a yield of 400 kT. This was a thermonuclear bomb, based on the warhead intended for the British version of the cancelled Skybolt air-launched cruise missile.

• Type C weighed 272 kg (600 lb), with a yield of 10 kT. This was the depth charge version for the Royal Navy, possibly based on the B57 weapon used by the United States Navy.

Type A and B weapons were carried by strike aircraft, including the Avro Vulcan, Blackburn Buccaneer, SEPECAT Jaguar, Panavia Tornado, and Harrier. At one time, eight Tornado squadrons were nuclear capable.

Following the 1997 General Election the Defence Secretary, George Robertson, ordered the Strategic Defence Review to reassess all of the UK's miltary commitments and equipment. Only Trident and the Eurofighter were exempt from the drawdown. One of the recommendations of this report was the withdrawal of all remaining WE177s, which was announced in March 1998. All of the weapons had been dismantled by the end of August that year, as Britain divested itself of all nuclear weapons other than the warheads of the Trident missiles of the Royal Navy's Vanguard-class submarines.

The withdrawal of the WE177 brought to an end four decades of RAF nuclear capability.