From Arabian Assignment: Operations in Oman and the Yemen, by David Smiley. (The Extraordinary Life of Colonel David Smiley Book 2; Sapere Books, 2020), Kindle pp. 11-12:
The British connection with Muscat dates from the early days of the East India Company in the seventeenth century, though the first treaty between Britain and the Sultan was not signed until 1798. An agreement followed two years later for agents of the East India Company to reside at Muscat, but the appalling climate killed off so many of them that it lapsed. Throughout the nineteenth century the British and the Sultan, who was then the most important ruler in the Gulf, collaborated closely in suppressing piracy, and the slave trade ceased in the Sultanate under a treaty of 1822. By a treaty of 1852 Britain (and France) recognized the independence of the Sultan, who still conducts his own foreign policy and maintains his own armed forces. Under subsequent agreements he may call on British help in time of trouble.
The trouble came soon after the old Imam’s death; the principal causes were Saudi ambition and, of course, oil. Ever since 1937 the Saudis had been trying to expand their territory beyond the edge of the Rub al Khali [the Empty Quarter], claiming frontiers with their neighbours — the States of the Aden Protectorate, the Sultanate, and the Trucial Sheikhdoms — which those neighbours refused to accept. After the Second World War the two superpowers, Russia and America, became increasingly involved in Arabia and the Gulf, the former pursuing an old imperial design, the latter attracted by fresh discoveries of oil: both with a common interest in reducing the influence of Britain. Encouraged by the new situation, the Saudis in 1952 suddenly occupied the strategic oasis of Buraimi, owned partly by the Sheikh of Abu Dhabi, a Trucial State, and partly by the Sultan of Muscat.
The Sultan gathered a force of between six and eight thousand tribesmen and, but for the ill-advised intervention of the British Government, would have expelled the intruders immediately, thus dealing a sharp blow to Saudi prestige and cementing the loyalty of the Omani tribes. When he failed to move, Saudi intrigue began to prosper.
The dispute went to international arbitration at Geneva, where the Saudi method, perfectly respectable in Arabia, of reinforcing their arguments with offers of large sums in gold to the members of the Tribunal caused such scandal that the President and the British delegate resigned in protest. At the end of 1955 the seemingly inexhaustible patience of Her Britannic Majesty’s Government ran out; in a sudden, bloodless coup the Trucial Oman Scouts descended on Buraimi, expelled the Saudi garrison, and established a garrison of their own and another of the Sultan’s in the Oasis. But the three year delay had been disastrous for the Sultan. The Saudis had made good use of the time to spread their influence in Oman, suborning the tribesmen with lavish gifts of money and arms. Moreover, a new Imam had arisen on the death of the Sultan’s old friend: one Ghalib bin Ali. A weak and colourless personality appointed by a cabal of three sheikhs but never formally elected, he was virtually a Saudi puppet; he possessed, however, a valuable ally in his brother, Talib, the Wali [Governor] of Rostaq, a brave, energetic and extremely ambitious leader with considerable military ability, who soon emerged as the driving force of the movement. Immediately after his election Ghalib, with his brother, toured his domain, setting up his own garrisons in his holy capital of Nizwa and in other strategically important towns and villages in the interior.