Having withdrawn formal recognition from the Pol Pot regime in 1979, the Thatcher government backed the Khmer Rouge keeping their UN seat after they were ousted from power in Cambodia by the Cambodian–Vietnamese War. Although Thatcher denied it at the time, it was revealed in 1991 that, while not directly training any Khmer Rouge, from 1983 the Special Air Service (SAS) was sent to secretly train "the armed forces of the Cambodian non-communist resistance" that remained loyal to Prince Norodom Sihanouk and his former prime minister Son Sann in the fight against the Vietnamese-backed puppet regime.