Sultan Qaboos bin Said, who has died aged 79, was the longest-serving ruler in the Middle East, transforming Oman from a medieval backwater to a modern state during more than four decades of supremacy.

In doing so he enabled Oman to avoid, to a large extent, the ostentatious squandering of oil revenue that characterised the Gulf states. Qaboos won respect far beyond his country for his skill in steering Oman along a middle path through the various minefields of Middle Eastern diplomacy. The Sultan was always careful to avoid extreme positions.

While remaining a loyal ally of the West, he retained close links with Iran. When President Obama sought to open a back channel to Tehran for secret talks over the nuclear programme, it was natural for the Americans to turn to Oman.

Qaboos helped to arrange a series of covert meetings between US and Iranian officials in 2013. When an interim agreement was reached in Geneva in November of that year imposing constraints on Iran’s nuclear programme, all the groundwork had been laid via the “Oman channel”, as diplomats called the Sultan’s discreet efforts.

Qaboos was also exceptionally close to the British. When he decided to create an air force in 1974 it was entirely in keeping that he would entrust this task to Air Marshal Sir Erik Bennett, an RAF officer who was then serving as air adviser to King Hussein of Jordan.

Bennett became the first commander of Oman’s air force and remained in this position until 1990. Even after his formal retirement, he remained a close adviser to the Sultan. Their personal bond grew stronger when the two men narrowly survived a car accident in Oman in 1995.

Earlier, the British had helped Qaboos to overthrow his father and seize power in 1970. The elder Sultan Said was a supremely conservative figure, content to preserve Oman in medieval aspic and spurn any drive for modernisation. After the old ruler was removed from the palace, an RAF plane flew him out of Oman and into exile in London.

Qaboos then received the help of the SAS to quell a guerrilla insurgency in Dhofar province, where his enemies were armed and supplied by the Marxist leadership in neighbouring South Yemen. Between 1970 and 1975 the SAS and assorted British advisers waged a secret war in Dhofar. They fought with such skill that their campaign is now taught as a textbook example of successful counter-insurgency.

The Sultan with the Princess of Wales in the Al Alam Palace, Muscat, 1986

CREDIT: JAYNE FINCHER/PRINCESS DIANA ARCHIVE/GETTY

Sultan Qaboos bin Said, the 14th ruler of Oman from the Al Bu Said dynasty, was born on November 18 1940 in Salalah. His mother was one of the Qara mountain people of Dhofar. He was educated by British tutors and at Sandhurst Military Academy.

During his training there, Qaboos received no special treatment. He was shouted at by sergeant majors, and housed in a dormitory along with his fellow officer cadets. Not all of them treated him as an equal.

He would later recall how one declined to share a canteen of water with him on exercise. Years later, the man concerned had occasion to call on Qaboos in Oman seeking a favour. “I thought long and hard about it,” said the Sultan, “but I refused to see him all the same.”

After passing out from Sandhurst, Qaboos spent a year as an officer in the British Army, serving with the Cameronians in Germany. When he returned to Oman in 1964, however, he found that his reactionary father now suspected his British education and feared his ambition.

At various stages, the young Qaboos was kept under virtual house arrest. His success in overthrowing Sultan Said marked a personal liberation.

The Sultan in uniform: he was educated at Sandhurst

CREDIT: BETTMANN

A week after removing his father, Qaboos visited the capital, Muscat, for the first time and promised a complete change from isolationism. “It was,” he said later, “a new dawn.”

At this time, Oman possessed only 12 hospital beds, six miles of surfaced roads and three primary schools – all of them for boys. Radios were banned and civilians were not allowed to drive. The gates of Muscat were closed every evening, and residents of the city going out after dark were required to carry lanterns.

One of the first contracts that Qaboos approved in 1971 was for the building of six schools and hospitals in the interior of Oman. Contractors experienced great difficulties because of the harsh terrain, but gradually modernisation got underway, government services were established in Muscat and elsewhere, and exiles began to return from abroad.

Their return to Oman and the entry of foreigners (not least Arabs from other countries) were closely supervised. Qaboos insisted that none of his reforms would threaten the traditions of the country. The wearing by men of national dress with the distinctive curved dagger, the khanjar, was encouraged; intermarriage with foreigners was forbidden. Tourism was not encouraged until the 1980s, and then only in a limited way, because of fears of “corrupting influences”.

During the early part of his rule, Qaboos’s concern to preserve the traditional fabric of society was overshadowed by the conflict in Dhofar. The origins of the Marxist rebellion dated back to the early 1960s, but its high-water mark of military success was reached in 1970 when the insurgents, 96 members of the South Yemeni-supported Popular Front for the Liberation of the Arab Gulf (PFLOAG), controlled all of Dhofar except for the RAF base at Salalah. The impetus for Qaboos’s coup had been a PFLOAG attack on an army post at Izki.

The new Sultan revived his army with a recruiting campaign and appealed for financial aid from Saudi Arabia and Abu Dhabi. Britain provided officers, both on secondment and private contract. Jordan loaned army instructors, India sent doctors and the Shah of Iran gave combat troops.

By 1975, after some bitter fighting, the last rebel town, Rakhyut, was recaptured, and on December 11 Qaboos declared in Muscat that the war was officially over. Diplomatic links with South Yemen were established, thanks to Kuwaiti mediation, 10 years later.

By the mid-1970s Oman’s oil industry was developing fast and Qaboos began investing the revenue in the development of his country. His policy was to develop both the public and private sectors without incurring external debt.

The scope of construction projects was wide, but the modernisation of Oman was carried out under the prudent gaze of the Sultan, and the carefully managed economy was one of his greatest legacies.

Within the Gulf, Oman enjoys a reputation of being the most efficient state and the one where the policy of training nationals to take over the jobs of foreigners is most effective.

This attitude of quietly getting on with what he considered to be best for Oman was reflected in Qaboos’s policies. For example, Oman alone of the Gulf states decided against joining Opec: Sultan Qaboos regarded this cartel as vulnerable to retaliation from those damaged by its decisions.

While he shared a deep commitment to the Palestinian cause, he failed to join the other Arab states in condemning Egypt for signing a peace treaty with Israel in 1979.

Of greater concern to Qaboos were relations between the various states in and around the Gulf. Worries about security in the region, following the revolution in Iran in 1979, and the outbreak of the Iran-Iraq war the following year, prompted Oman to join the Gulf Cooperation Council in 1981.

At the same time, Qaboos was not afraid to admit his country’s vulnerability; despite protests from several Arab states he signed a military access agreement with the United States. Joint manoeuvres were carried out to test the readiness of the US Rapid Deployment Force.

Later, Sultan Qaboos allowed the US to use the Omani air force base on Masirah island as a staging post during its abortive attempt to free American hostages from Tehran in 1979. But American influence generally on Oman was not strong, since Washington regarded the country as a British theatre.

Sultan Qaboos with the Prime Minister, Margaret Thatcher, at 10 Downing Street, 1982

CREDIT: KEYSTONE/GETTY IMAGES

By a quirk of cartography, Oman possesses an enclave that controls the southern shore of the Strait of Hormuz, at the entrance to the Gulf. During the Iran-Iraq war between 1980 and 1988, Oman adopted a key role in ensuring freedom of navigation.

The Sultan’s small but well-equipped navy – helped by British officers – worked closely with other navies in containing the threat to shipping from Iranian forces.

After the Iraqi invasion of Kuwait in 1990, Qaboos was among the Arab leaders who believed that the crisis could be resolved without the use of force. He personally tried to mediate between Iraq and Kuwait.

When it became clear that Saddam Hussein could not be persuaded to withdraw, Oman then helped America and Britain to wage the Gulf war of 1991 that liberated Kuwait from Iraq’s grasp.

As much as the Sultan was pragmatic in foreign policy, he was also a man of contradictions in his public and private lives. Although portrayed as a hero to his people, he was often aloof and solitary, spending long periods away from Muscat at his favourite palace in Salalah.

Committed to the Arab cause: the Sultan in 2000 with the Palestinian leader Yasser Arafat

CREDIT: MOHAMMED MAHJOUB/AFP VIA GETTY IMAGES

Inside his various palaces the Sultan had a fine collection of clocks and ornaments, including figures of horses and other animals. He was also an opera lover – everything from Gilbert and Sullivan to Verdi. When in London he made a point of visiting Covent Garden. Back in Muscat he sponsored the creation of a full symphony orchestra.

Qaboos was most at ease with his British advisers, particularly Sir Erik Bennett, or when out on manoeuvres with his troops. He distanced himself from his close relatives. In 1976 he married a daughter of his uncle, Tariq bin Taimur; but the marriage ended in divorce without issue.

Qaboos never remarried, leaving no heir to the throne, and providing a popular topic of gossip in a society where childlessness carries a social stigma.

The Sultan was a natural autocrat: for most of his reign he chose to hold the positions of prime minister, foreign minister and defence minister himself. He allowed some limited political reforms, establishing a nominated Consultative Council in 1981 which was expanded to include women in the 1990s. Qaboos also allowed Omani women to join the civil service, the police and the armed forces.

But opposition was seldom heard: the local media was servile and supine; foreign correspondents found it difficult to obtain visas. In 1994, around 200 suspected Islamist radicals were arrested. Several were sentenced to death, but Qaboos commuted this punishment to imprisonment.

In 1995 the Sultan had a brush with death when the car in which he was travelling was involved in a serious accident. Qais al-Zawawi, the deputy Prime Minister for Economic and Financial Affairs, was killed. Sir Erik Bennett was badly hurt, but Qaboos escaped unharmed.

Mystery surrounded the exact circumstances of the crash. But thereafter security around the Sultan was strengthened, and on his annual tours of the country with an entourage of ministers and officials he was noticeably less accessible to the public than before.

His successor as Sultan of Oman was reported to be his cousin Haitham bin Tariq Al Said.

Sultan Qaboos bin Said, born November 18 1940, died January 10 2020