"A) To pass under SPANISH sovereignty in accordance with the terms proposed by the SPANISH GOVERNMENT to the Government of the United Kingdom on 18th May, 1966 (which terms are set out in the Schedule to the Gibraltar (Referendum) Order 1967).B) Voluntarily to retain their link with the UNITED KINGDOM with democratic local institutions and with the UNITED KINGDOM retaining its present responsibilities.

On 18 May 1966, the Spanish Minister of Foreign Affairs, Fernando Castiella made a formal proposal to Britain comprising three clauses:[2][3] The options presented to Gibraltarians in a referendum were:[4] A new constitution was passed in 1969.

In 1969, the Spanish government closed the border between Spain and Gibraltar, cutting off all contacts and severely restricting movement.

The Special Committee on Decolonization was informed in advance of the referendum and invited to observe.

[5] The invitation was declined and instead the UN General Assembly passed Resolution 2353, which requested that the United Kingdom enter negotiations with Spain (then under the dictatorship of General Franco) and criticised the United Kingdom for holding a referendum.