Established by the British Government under UN Security Council Resolutions 217 and (by 9 Apr 1965) UNSCR 221, to enforce economic sanctions against Southern Rhodesia (now Zimbabwe), primarily to prevent the flow of oil to the country from the East African coast. The patrol began with two frigates and an RFA, initially supported by a carrier (until mid May 1966), whilst the RAF organised its local base of operations for air cover, with Shackletons from Majunga between 16 Mar 1966 and Jun 1971, until Madagascar obtained its independence from France and the basing agreement ended. By Mar 1971, this had reduced to one warship and one RFA in support. Almost 80 Royal Navy warships took part in this operation at various times over its 10 year lifespan. The Operation was called off when Mozambique gained independence from Portugal, HMS Salisbury the last warship on patrol departed and the UK Treasury breathed a huge sigh of relief.