On 11 November 1965, Ian Smith's Rhodesian Front Government proclaimed the Unilateral Declaration of Independence (UDI) from the United Kingdom.

On orders from the UK, the then-Governor of Southern Rhodesia, Sir Humphrey Gibbs, immediately sacked Smith and his cabinet.

This action was ignored by Smith, who stated that the UDI brought into immediate force a new constitution which dispensed with the position of Governor – and with it, his reserve power to sack them.

Instead, Whitehall insisted that Gibbs was the Queen's only legitimate representative, and hence the only lawful authority in what it still maintained was the Colony of Southern Rhodesia – a position backed by most of the international community.

For five years, Smith and his government continued to profess loyalty to Queen Elizabeth II and recognised her as Rhodesia's head of state.

Like the UDI and the declaration of a republic, Zimbabwe Rhodesia was unrecognised internationally and in 1979, Britain resumed control of the rebel colony under the Lancaster House Agreement.