Vulcans in Camera - Yellow Sun.

Yellow Sun was the megaton free-fall bomb built to Operational Requirement 1136. The top picture shows Yellow Sun Mk1. The forward centre section contains the spherical 500 kiloton Green Grass warhead that was also fitted to this weapon's predecessor, the interim megaton weapon Violet Club. Green Grass was never tested but retained the outside shape of an experimental single-stage thermonuclear warhead called Green Bamboo that was prepared for nuclear tests in 1957 but withdrawn. With a core of uranium 235, Green Grass was just a huge atomic warhead and, with the US Mk-18, is believed to have been the largest weapon of that type ever to have been deployed. The lower picture shows Yellow Sun Mk2. In 1958, Britain resumed its Special Nuclear Relationship with the United States producing an Anglicised version of the US W28 thermonuclear warhead. The British version was known as Red Snow. Red Snow was fitted to Yellow Sun Mk2 and the Blue Steel missile. With a yield of 1 megaton, Yellow Sun Mk2 was Britain's first hydrogen bomb to become operational. Yellow Sun Mk1 was introduced in 1959 and withdrawn in 1963. Yellow Sun Mk2 was introduced in 1961 and was withdrawn in 1970.