In 1955, the Sultan of Oman resorted to the use of force in trying to expel invading Saudis in the territory. The Trucial Oman Scouts, which were led by British Officers and NCOs, were imported to eject the Saudi garrison. However, in the previous three years the Saudis had been spreading their influence in Oman. A breach between Oman and Muscat had occurred and a disagreement over the right to grant oil concessions was exploited by the Saudis and Radio Cairo to exacerbate relations between the Sultan of Muscat and Imam Ghalib Bin Ali of Oman. In December 1955, the Sultan sent troops of the Muscat and Oman Field Force to occupy the main centres in Oman, including Nizwa and Ibri. Under the terms of a 1920 treaty, the Sultan of Muscat was responsible for the external affairs of Oman. An oil concession, as far as he was concerned, was an external matter. The Omani leader resorted to open rebellion. In July 1957, the Sultan's forces were withdrawing but were repeatedly ambushed, sustaining heavy casualties. The British officers brought a few survivors back but many deserted. The Imam occupied Nizwa and the Sultan immediately asked for British assistance.
Within a month, two companies of the Cameronians were flown in form Bahrain and two squadrons of Trucial Oman Scouts were moved into Ibri. One troop of the 15/19th Hussars was flown in with their Ferret scout cars from Aden. The opposition melted away and Nizwa was recaptured unopposed. RAF Venoms flew sorties from RAF Sharjah, RAF Ghalib, RAF Talib and RAF Suleiman, bringing very accurate rocket fire to bear on the forts in the rebel town.
The Cameronians were withdrawn to Aden after the events of July. The Sultan's army was redesignated the Sultans Armed Forces and a new commander was appointed, Colonel David Smiley, seconded from the British Army. The remainder of the British contingent was provided to expand and reorganize the indigenous military forces and consisted of a few British regular officers seconded to SAF, a handful of Royal Marine Commandoes, Royal Corps of Signals and some medical personnel. A troop of armoured cars from 13/18th Hussars and a few RAF pilots made up a total of fewer than 50 British servicemen of all ranks. Somewhat less than the 10-20,000 strong army that Radio Cairo claimed was deployed in Oman. The SAF was successful in containing the rebels in the Jebel Akhdar in late 1957 and early 1958. Throughout 1958, mines on the road between Muscat and Nizwa destroyed about 20 military vehicles a month. Between August and December A Squadron of Life Guards succeeded the Hussars and lost 80% of their Ferret scout cars from mines, although with few casualties. The RAF, who continuously patrolled the Jebel, reported rebel anti-aircraft fire from a .5inch Browning.
Smiley found it increasingly clear that he needed to capture the Jebel but could not do so with his current forces. In June 1958 the Secretary of State for War, Christopher Soames, visited Sharjah and Smiley met him and asked for additional troops, especially Commandoes, Paratroopers or SAS. Smiley gleaned that 22 SAS were returning from Malaya to England in July and suggested a short detour for them on their way home.
The SAS arrived in mid-November; D Squadron, commanded by Major John Watts was organized into four troops of about 16 men each. The SAS were in action within days. In December, an SAS troop established itself atop the Jebel with twenty dismounted Life Guards. Most of the Life Guards were national servicemen with little or no experience of battle. With the foothold secured, the SAS attacked the nearby rebel strongpoint Aquabat al Dhafar.
Under a protective barrage of machine gun and mortar fire, the SAS scaled the sheer cliffs of the Jebel and surprised the rebels in their caves, close-quarter fighting ensued and the SAS inflicted some casualties without loss to themselves. This engagement convinced Smiley and Watts that a single squadron of SAS could not take the Jebel alone, but a second squadron would be needed to do the job. A second squadron from 22 SAS was sent out, with the proviso that all British troops were out by April 1959, by which time the UN was due to discuss the area.
On 1st January, Lt-Colonel Tony Deane-Drummond, the commando officer of 22 SAS arrived in Muscat. A Joint tactical headquarters was set up at Nizwa on 8th January. On 12th January A Squadron 22 SAS flew in from Malaya and Major John Cooper commanded it. A Squadron immediately moved in to give D Squadron a rest and acclimatize as fast as possible. It was decided that a direct assault on the Jebel would be made on the night of 25th/26th January, from the shortest route. There was no path but the route chosen appeared to be feasible and unguarded. Various diversions were undertaken, including offensive patrols by the SAS and Trucial Oman Scouts, diversionary attacks in the Tanuf and Izki areas, and false intelligence was fed to the rebels. On the night of the attack, of the 100 pickets guarding the Jebel only one was posted on the track the SAS used. The operation was postponed 24 hours due to low cloud.
At 2100 hours on the evening of 26th January, A and D Squadron of 22 SAS supported by dismounted Lifeguards assaulted the Jebel. Some tribal irregulars were involved and a platoon of the Muscat Regiment was involved. RAF Venoms and two helicopters were available. The 5.5-mm guns of the Sultan's forces provided artillery support for the operation.
A third of the way up the side of the Jebel, a stray snipers' bullet exploded a grenade in an SAS troopers pack, seriously wounding the trooper and two other men. All were evacuated by helicopter but two of the three died from their wounds the next day. The leading SAS troopers came under 0.5inch Browning fire soon afterwards from the only picket guarding their route. This was silenced in minutes and the SAS made their way to the top. The leading SAS Squadron made the top by first light. The Lifeguards, close on the heels of the SAS, set up their machine guns and secured the heights. Three RAF Valettas dropped 30,000lb of equipment, ammunition, food, and water to the troops. The Venoms made low-level passes over the plateau without finding any targets. The supplies had been mistaken for parachutists and the three rebel leaders had fled. The SAS pressed on unopposed and discovered hastily abandoned intelligence, arms, and ammunition. The tribal irregulars now had the task of establishing the Sultan's authority throughout the area. The rebel tribesman gave up as they were told that no reprisals would be taken against them, giving up great stockpiles of arms carrying Saudi Arabian Army markings. British troops and the SAF patrolled the Jebel for two weeks and the area was extensively mapped and a landing strip constructed. A company of the Northern Frontier Regiment (SAF) established a camp by the airstrip and a British officer attached to SAF was appointed Military Governor of the Jebel Akhdar.
The rebel leaders had moved to the coast and from there they managed to reach Saudi Arabia. They laid low for six months, retaining the loyalty of a hard core of rebels who remained in Oman. They were again mining the roads by summer 1959. Smiley realized that the SAF had insufficient numbers to stop the flow of mines from Saudi Arabia and got agreement to raise a paramilitary force, the Gendarmeries, which with the SAF and Royal Navy reduced the arms smuggling. A system of rewards and reprisals helped to get the message across and Smiley continued to build up the strength of the SAF after the SAS left in March and the Lifeguards in May 1959.
When Smiley left Oman in 1961, the SAF was at strength of 2,000 men. There was an uneasy peace in the area at the time. During the campaign, between January 1958 and January 1959, the SAF suffered 8 killed and 51 wounded. The Trucial Omani Scouts had 1 British officer killed and the British regiments lost 3 SAS, two Royal Marines and one member of the Royal Corps of Signals and six wounded, one SAS, three Lifeguards and two Royal Marines.
Cairo Radio had reported that in the attack on the Jebel Akhdar, 120,000 British troops had been employed and Moscow embellished the story further, claiming 13,000 paratroopers had been dropped. In fact, barely 1,000 men had been involved, of which only 250 were British.