OVERVIEW: The WE.177B was a high-yield, air-dropped nuclear bomb developed by the United Kingdom for tactical and strategic roles.

DETAIL: The WE.177B was one of three variants in the WE.177 family, distinguished by its significantly higher yield. Designed as a dual-capable weapon, it could be used for both airburst and ground-target effects depending on the mission profile. The bomb featured a boosted fission primary and thermonuclear secondary stage, employing the Red Snow physics package derived from the U.S. W-59.

It was built for delivery by fast jets under a variety of release conditions, including low-altitude toss bombing or parachute-retarded delivery. Its compatibility with British strike aircraft like the Buccaneer, Tornado GR1, and Vulcan made it a core component of the UK’s tactical nuclear strike capability during the Cold War. A key feature was its low radar cross-section and high aerodynamic stability.

The WE.177B remained in service from 1966 until its withdrawal in 1995. It was stored under strict NATO protocols and allocated for both national deterrent and NATO-assigned nuclear roles.

NOTE:
IOC: 1966
Operators: United Kingdom (Royal Air Force, Royal Navy)
Platform: Blackburn Buccaneer S.2B, SEPECAT Jaguar GR1, Panavia Tornado GR1, Avro Vulcan B.2, Phantom FG.1
Conflicts: No known combat use; deployed as part of NATO Cold War nuclear strategy

SOURCE:
UK National Archives ; British Ministry of Defence (MoD) ; Federation of American Scientists (FAS) ; Jane’s Weapons: Air-Launched ; Atomic Weapons Establishment (AWE) https://fas.org ; https://www.gov.uk/government/organisations/ministry-of-defence ; https://www.awe.co.uk ; https://www.janes.com