Major Gordon Browne was  a senior MI5 officer who reassured Macmillan over the Profumo scandal and argued the government’s case during the Spycatcher affair

When the Profumo affair broke in 1963 there was panic that Britain’s secrets had been betrayed to the Russians. John Profumo, the secretary of state for war, was having an affair with Christine Keeler, who was also sleeping with Yevgeny Ivanov, the naval attaché at the Soviet embassy. Had she been passing on to him intelligence she had learnt from a key cabinet minister?

The embattled Harold Macmillan government knew she had not, largely because Gordon Browne, deputy head of MI5, had done a thorough job as a special investigator for Britain’s intelligence agency. As soon as the scandal broke, he had been seconded to Roger Hollis, the MI5 director-general, to look at another potentially devastating leak, only months after the defection of Kim Philby.

The agency already knew that Profumo was sleeping with Keeler, but never believed he was a security threat. It was also already monitoring Ivanov and concluded that he was not a KGB agent, but merely a libidinous Russian making the most of an opportunity.

Browne’s conclusions were upheld by Lord Denning, the judge who investigated the affair. His report said that there had been no breach of security. It did not save the Macmillan government. Nor did the public learn anything about Browne’s role in MI5. The agency still did not officially exist and its role was highly secret.

Browne was used to living in the shadows. He had been with MI5 almost since its reorganisation after the Second World War and had played key roles countering Soviet spying, overseeing intelligence in the Commonwealth and instituting proper training for MI5 agents.

Until the mid-1960s, MI5 officers were expected to learn on the job how to shadow targets, filter intelligence and keep check on domestic threats to British security. But at the height of the Cold War there was no longer room for amateurs.

Browne’s work often took him overseas. In 1961 he travelled to the Bahamas, Jamaica, Trinidad and Bermuda to check on security. The next year he attended a conference in Washington on British Guiana, a colony where there were fears of communist infiltration of the independence movement.

President Kennedy sent Macmillan a message thanking him for the high quality of the British delegation. In 1962 Browne went to Cyprus to build an intelligence relationship with the newly independent country. There were confidential talks with Greek and Turkish Cypriot officials, but also lighter moments when he was entertained by intelligence officers and their wives, who served him stewed sparrows and took him to a show involving male and female strippers.

A year later he was sent to Singapore, a central intelligence headquarters for the Far East. Indonesia had just tried to invade the newly created Malaysia (the “Konfrontasi” crisis) and President Sukarno had communist backing for his attacks on the Malaysian part of Borneo and low-level harassment. With British and Commonwealth forces involved, intelligence was vital.

Browne earned a reputation within the agency as a superb organiser, a skill he had learnt during his wartime service in Europe and Burma. MI5 officers were complaining of poor administration, old systems and slow central processing. Browne was charged with bringing in computers to assist in the sifting of intelligence, and from 1969 he ran the technical side of MI5, known as A2.

His predecessor had had a heart attack and resigned abruptly without leaving any record of what he did. The secretary had also departed. The main liaison with the Government Communications Headquarters (GCHQ), a mathematician, choked to death on smoked salmon at the Army & Navy Club and another important colleague also had a heart attack.

Browne therefore had to rebuild the department from scratch, despite knowing nothing about the job. He started by asking each person what they did and why, and then organised all the technical staff, such as transcribers and listeners. The key targets were the Russians, the IRA and communists in Britain.

There were further visits to Ottawa and Washington to liaise with the Mounties and the CIA, and to Glasgow to appease the local police who complained they had not been sufficiently briefed by MI5. Browne helped ease the frosty atmosphere by revealing over lunch that he had Scottish ancestry.

Perhaps the most difficult of his overseas trips came after his retirement in 1976. In 1986 Peter Wright, a former MI5 officer, published his memoir, Spycatcher, in Australia. (It was banned in Britain.) The government sent William Armstrong, the cabinet secretary, to testify in Britain’s legal attempt to prevent publication of the book on the grounds that Wright had broken the Official Secrets Act.

Browne was sent to Sydney to refute Wright’s claim that he had never been briefed about security. As head of training, he had explained MI5’s workings to all trainees. Wright asserted in his book that Roger Hollis had been a Soviet intelligence agent, that MI5 had plotted against Harold Wilson and that British intelligence was working without proper permission. The government was keen to refute his allegations while suppressing all details of how the agency worked.

The affair turned out badly. Malcolm Turnbull, representing the Australian publisher, ran rings around Lord Armstrong, who was forced to admit he had been “economical with the truth”. Browne was prevented from giving evidence, lest he say things that had not been authorised by the MI5 director-general. The attempt to prevent publication failed, and Spycatcher was published in Britain the next year. Turnbull made much of his success and went on to become the prime minister of Australia. Browne was then called in to clarify the rules around security.

Gordon Browne was born in Tamil Nadu, south India, at an army hill station in 1916, to William and Elizabeth Browne (née McArthur-Moir). In his early years he was constantly on the move as his father, a doctor with the Royal Army Medical Corps, was assigned to different posts — Shimla, India, in 1918, Malta in 1922, Aldershot in 1924 and Bath in 1928, when his father was sent to the army medical service in Cairo.

Educated at Cheltenham College, then mainly a military school for future officers, he was farmed out to relatives during the holidays, while his parents were posted back to India. Holidays were sometimes spent in Scotland, where he once nearly shot himself at the age of 14 while hunting rabbits.

After two years at Sandhurst he joined the Suffolk Regiment. His commission into 12th Foot was one of the few signed by Edward VIII before his abdication. Sent to Malta in 1937, he was in charge of signals and provisions and boxed as a light-heavyweight for the regiment.

Back in Britain a year before the war, he did a signalling course and was sent to Plymouth to prepare troops for conflict. As war loomed, he sent a telegram to Molly Gray, whom he had met at a dance five years earlier, asking her to marry him. They married three days after war broke out and had four sons: Richard, a retired BBC engineer; Robin, a retired GP; Sir Nicholas, diplomat and ambassador to Tehran and Copenhagen (obituary, January 22, 2014); and Julian, a retired journalist and publisher.

Browne’s wartime service began in France with the British Expeditionary Force. Sent to France and then to Belgium when the Germans invaded, he was forced back to Dunkirk where he helped to organise British troops who had made their way to the beaches, where he was evacuated.

In 1941, after staff training at Camberley, he was promoted to brigade major and posted to Colchester and then Londonderry. On one night exercise he was asked to report to London. He took an American bomber and noticed that the crew played poker while the aircraft flew on autopilot. He was then “volunteered” for Orde Wingate’s Chindit force in Burma. He arrived in Delhi and began preparing for jungle warfare, where the hills were steep, the rain continuous, the mules the only transport and wild pigs were often mistaken for enemy.

In 1944 he was sent to Imphal and ordered to capture a hilltop behind Japanese lines. It was almost a suicide mission. They were attacked two nights running; the soldier next to him was killed and they were forced to pull back. Dysentery affected many troops. Browne became unable to walk and was sent back by Jeep to Imphal.

After a further year in India, which included mediation between Hindus and Muslims and imprisoning an embezzling British officer, he returned to Britain in 1947 and worked in the war office on military security. This led to co-ordination with MI5 and, after a nightmare exercise on Salisbury Plain in wet snow, he resigned from the army and joined MI5 as an intelligence officer.

The early years were mostly taken up with keeping records on communists in defence industries and others of interest to intelligence. In 1953 he attended the Three-Power Conference in Bermuda with Eisenhower, Churchill and Joseph Laniel of France.

Churchill, by then 80, could not reach the sea so his secretary was instructed to fill his hat with seawater so that he could feel what it was like. Browne was responsible for briefing the press and made himself unpopular by abruptly ending the session. The Daily Mail called him the Man in the Raincoat.

After retirement to West Malling, Kent, marked by the award of a CBE, he spent time travelling, looking after the family home and garden and adding his robust voice to local campaigns against development and new roads. His wife died in 2000 and he spent his final six weeks in a retirement home, where the staff pressed him for memories of MI5. “I could tell you about that, but then I might have to make you disappear,” he replied.

Gordon Browne, CBE, was born on November 30, 1916. He died of natural causes on October 17, 2019, aged 102.