(For the military operation in Bosnia, see Operation Grapple (Yugoslavia).) Operation Grapple, and operations Grapple X, Grapple Y and Grapple Z, were the names of British nuclear weapons tests of very early hydrogen bombs. These tests were carried out from 1956 until 1958 at Malden Island and Christmas Island in the Central Pacific Ocean. Nine nuclear explosions were executed during these series of nuclear weapon tests, culminating in the United Kingdom's becoming the third recognised possessor of thermonuclear weapons.