紅鬍子
At the time, the UK's only tactical nuclear weapon was Red Beard, a relatively large weapon of weight. While work continued on Cleo, it was decided to adapt it as a weapon of its own to replace Red Beard, as the 'Improved Kiloton Weapon'. The adapted version of the primary, now the only part of the physics package, became 'Katie'. Katie would be used in a new bomb casing to produce WE.177A, replacing Red Beard with a weapon of roughly 1/3 the weight, and much smaller size. WE.177A would also be used by the Royal Navy, both for surface attack, as well as a nuclear depth bomb, or NDB.