Denis Healey, who has died at the remarkable age of 98, was a practical man of power and of paradox. A fastidious intellectual with puritanical outlook and ability, his natural self-confidence was entrenched early in life by a double first from Balliol college, Oxford, and five war years as a fighting soldier. But, throughout his 50-year career as a Labour politician, Lord Healey, the culture-loving aesthete, was also a bruiser and a bully whose style helped deprive him of his party’s leadership and the chance to confine Margaret Thatcher to a one-term premiership.

A reforming defence secretary (1964-70) who abandoned over-stretched Britain’s anachronistic role in the retreat-from-empire 1960s, he went on to became Labour’s indestructible chancellor of the exchequer (1974-79) during the worst peacetime crisis since the Great Depression.

His tenure included the humiliation of the IMF loan of 1976, near hyper-inflation – peaking at 26.9% in 1976 – and protracted battles with militant unions over pay. The cumulative outcome was a Labour split and the Thatcherite counter-revolution of the 80s, which gradually reversed much of the postwar social democratic settlement to which Healey had devoted his life.

So, for all his evident brain power and stamina, his resilience and loyalty to his party – a combination conspicuous even in a talented generation that included Harold Wilson, Jim Callaghan, Michael Foot, Roy Jenkins and Tony Crosland – Healey became neither foreign secretary, a post for which he was supremely well-qualified (“I would have loved that”), nor prime minister.

Denis Healey and Tessa Jowell in 1978. Photograph: Press Association

Mainstream voters admired him and enjoyed his pantomime talent for playing the fool ( “silly billies” was a favourite Healey catchphrase). They loved his bushy eyebrows. But too many of Healey’s colleagues had been bruised too often by his caustic tongue (“out of your tiny, Chinese minds”) and flippancy to forgive him until it was too late. Twice defeated for the Labour leadership – in 1976 and, crucially, in 1980 – he was twice denied the foreign office by a resentful Wilson. He became instead one of the “best prime ministers Britain never had”.

Healey never learned how to dominate the Commons. But in old age he regretted he had not tried hard enough to win: “I think I could have made it if I’d tried.” The truth was he was a loner, both unwilling and unable to cultivate potential allies or tolerate fools for long. “Well, you’re an ignorant bugger anyway,” he once told a reporter who missed an obscure literary reference. As another robust loner at No 11, Kenneth Clarke, would later discover, it is rarely enough in politics to say: “I’m here if you want me”. Always wanting to “do something rather than be something”, Healey was too busy to be a faction-fighter or plotter.

It never stopped him enjoying life to the full. He called his memoirs, The Time of My Life and used them to parade a range of interests – hinterland, he called it – that few at the top of high-pressure 20th-century politics could match. Despite a gruelling workload, even as chancellor Healey clung to his youthful enthusiasms for music, literature (from poetry to thrillers), painting and theatre. In pre-digital times he always carried a camera, usually managing to slip away from a dull conference abroad to visit a gallery, or sleep beneath the desert stars on a palace roof in Yemen.

The sheet anchor of his career was an intensely happy 65-year marriage to the future biographer Edna Edmunds, the crane driver’s daughter whom he had met at Oxford and married in December 1945. Before achieving late literary success, she sacrificed her own ambitions to support Healey’s all-consuming career and raise their three children, though they were as close a family as opportunity allowed. For his part, her husband gave her romantic devotion, never afraid to express it in extravagant terms in public, accompanied by a kiss or Shakespearean love sonnet. Lady Healey died in 2010.

The MP for Leeds East at the 1963 Labour conference. Photograph: Rolls Press/Popperfoto/Getty Images

By 1945, Healey had already packed in a lifetime of experiences denied to future generations. A beach master in charge of logistics (US actor Lee Marvin was another) at the bloody Anglo-American Anzio landings in Italy (1944), Maj Healey would turn down a lieutenant colonelcy as well as an Oxford fellowship to study the philosophy of art in favour of politics. After making a ferocious class warrior’s speech at Labour’s pre-election conference in 1945 (“Your speech may have cost us victory,” he was warned) he narrowly failed to win Tory Pudsey in Clem Attlee’s landslide.

Losing a marginal seat was probably a lucky escape. He became instead international secretary of the Labour party, nominated by party grandees Hugh Dalton, Harold Laski and Nye Bevan. It was a hugely important post when British Labour’s prestige was at its peak in the ruins of post-war Europe, and Healey quickly became a key adviser to the new foreign secretary, the powerful but unlettered Ernie Bevin, writing a stream of pamphlets articulating Bevin’s position against the neutralist and pro-Soviet Left.

Healey himself had briefly been an Oxford communist in the pre-war “popular front” years, favoured by party bosses until he left in 1940. But as the contours of the Cold War emerged, Healey the youthful class warrior shed the widely held sentimental regard (“rhetorical candy floss”, he called it) for Stalin’s Russia quicker than most: as a veteran union leader, Bevin had never shared it. By the time he became MP for solidly safe and loyal Leeds SE (later Leeds East) in 1952, he was transformed into a combative figure on the right of the party, identified with pro-American, pro-Nato sentiments: Russian subversion of postwar East European regimes had converted Healey to deterrence and containment. It was anathema to the anti-American and New Statesman left in the polarised 50s and to unilateral nuclear disarmers after CND was launched in 1956.

Denis Healey with his wife Edna at home in 1976. Photograph: Press Association

As such, Healey was an ally, but never an acolyte, of Hugh Gaitskell, fellow Leeds MP, and Attlee’s successor as party leader in 1955. When Gaitskell died unexpectedly in 1963, Healey could not back the volatile George Brown, voted for Jim Callaghan but ended up with Wilson, who had manoeuvred himself into being the left’s candidate. Never a fan, Healey’s private contempt for Wilson’s opportunist mind (“an awful prime minister”) deepened in office. Wilson was tempted to sack him, but by now Healey was too substantial a figure.

Healey’s father, Will, a self-made engineer of Irish, possibly Fenian, stock uprooted his family from Kent – where Denis was born in 1917 – to Yorkshire when he became head of Keighley Tech. The old-fashioned rigour of Bradford Grammar School – redolent of Alan Bennett’s History Boys – and his own ferocious stamina led Denis to an Oxford scholarship, buttressed by long adolescent bicycling trips across England, then Europe; Healey’s first taste of abroad and its artistic splendours. The tone of his letters and diaries of the period were acute, but both intellectually condescending and chippy about social hierarchy, including the “outdated bourgeois fripperies” of the Oxford Union.

Healey duly mellowed and lived the last third of his life in the picturesque village of Alfriston, close to Glyndebourne in bourgeois Sussex. But he never lost his early disdain. As chancellor, he would deny having threatened to “tax the rich until the pips squeak”, but he uttered many similar threats to placate his increasingly left-leaning party, even as he came to realise the folly of tax rates which touched 98% (at least in theory) on “unearned” investment income.

Healey’s apprenticeship for the most gruelling peacetime chancellorship since the 30s had been the MoD, where a combination of decolonisation, economic weakness and integration of the three feuding services into a single ministry – all policies begun under the Tories – occupied much of his energy. Determined to keep the runaway defence budget he had inherited from the Conservatives below £2bn – around 7% of GDP – he cancelled aircraft carriers and successive fighters, the British TSR-2 and (defeated in cabinet by the Treasury) the American F-111. The navy was furious. He slashed Britain’s bases and commitments in the Caribbean, Mediterranean, Gulf, Aden and the Indian Ocean, allowing the US to establish its own great base at Diego Garcia in the process. But successive economic crises, culminating in the humiliating devaluation of sterling (from $2.80 to $2.40 to the pound) in 1967, required no less than five budget-cutting defence reviews.

From the start, Healey the realist had opposed the Anglo-French plot with Israel to seize back the nationalised Suez Canal in 1956 – Britain and America had provoked Nasser, he protested – but was keen not to leave needy allies like Singapore’s Lee Kuan Yew in the lurch. He embraced the successful low-intensity guerrilla war – in which Paddy Ashdown served as a young officer – to protect Malaysia’s provinces in Borneo (1962-66) from Indonesian aggression. But he refused to copy the high-altitude bombing tactics the US was disastrously adopting in nearby Vietnam. Labour Britain stayed out of that quagmire, as it did when rebellious white settlers declared independence (UDI) in Rhodesia in 1965. By confining themselves to only token military threats to end UDI, British politicians were aware that, if asked to fight a “kith and kin” war, its own military might rebel, too, as the French army had just done over Algeria.

Healey had opposed grandiose Tory plans for a fully independent, home-made nuclear deterrent. But he shared fears that Washington might one day cut a deal with Moscow and leave Europe vulnerable, so embraced the semi-independent Polaris, later Trident, compromises that still survive. Unlike the Europhile Roy Jenkins (along with Edward Heath, a student friend from Balliol), on Britain’s membership of the future EU Healey was a gut sceptical, always anti-federalist. But he accepted the economic case for membership when Heath finally took Britain into the then-EEC in 1973. A decade later, he helped persuade Neil Kinnock of the need to embrace both Europe and the bomb if Labour was ever to defeat Margaret Thatcher. Later still, Healey, ever the pragmatist, would turn against both. Circumstances had changed, he would explain.

Denis Healey in 2006. Photograph: Murdo Macleod/the Guardian

Pragmatism in response to a fearsome combination of events was to be the hallmark of Healey’s chancellorship, learning economics (he had studied classics) on the job to dominate the Treasury mandarins with a mixture of “excitement and fear”. When Labour unexpectedly won the miners’ “who governs Britain?” election in February 1974, he inherited quadrupled oil prices, a runaway credit boom and rising inflation, a balance of payments crisis and militant union leaders (“an appalling lot”), plus the secondary banking crash and Treasury spending estimates that repeatedly proved wrong in both directions.

Healey initially sanctioned higher taxes and borrowing to sustain demand, protect jobs (at 1.25m, unemployment was deemed too high) and win the October 1974 election (by just three seats). But he rapidly decided Labour’s economic guru, Keynes, had failed to understand the disruptive power of both trade unions and world financial markets. He spent five years trying to appease both and to get credible budgets through a divided cabinet without provoking resignations and a 1931-style collapse.

As Healey’s strategy crumbled and the crisis deepened, sterling dropped below $1.70 and the chancellor was forced to abandon a flight to the IMF’s September 1976 meeting in Manila. Driving from Heathrow straight to Labour’s angry Blackpool conference, the brief, defiant speech he was allowed to make was heckled from the floor. This time he stood his ground. Defeated by Callaghan for leader in the five-man contest that followed Wilson’s 1976 retirement (Healey had abused the left in a Commons confidence debate just days earlier and got only 30 votes), the pair now warily cooperated. By December they had forced through enough spending cuts to secure a £1.9bn loan from the IMF (in return for £2bn worth of cuts) to tide Britain over and appease the markets. It was a major trauma comparable to John Major’s sterling crisis in 1992 or that of Gordon Brown when the banking system imploded in 2008. Yet subsequent data showed the borrowing gap had been exaggerated. Had he known, the IMF loan, could have been avoided, Healey would say.

Strikes continued. After Heath’s attempt at statutory incomes policy, the unions would only accept a quasi-voluntary system in return egalitarian policies – a flat-rate £6pw rise for all in 1975 – and Foot’s much-vaunted “social contract”. Over three years, spending fell by 8% in real terms, interest rates plunged from 15% to 5% and resumed growth touched 3% by 1978. But when Callaghan demanded a 5% ceiling on pay in 1978 (Healey felt a “single figures” ceiling more realistic), union impatience shattered. The resumed militancy of the Winter of Discontent, coupled with Callaghan’s decision to postpone the expected 1978 election, all but guaranteed Thatcher’s mandate for fundamental change.

Healey’s battles did not end with Labour’s ejection in 1979. Beaten in 1980 by Michael Foot to succeed Callaghan, he only narrowly (50.4% to 49.6%) fought off a divisive 1981 challenge for the deputy’s job by Tony Benn, who had swung left. It was the unions’ short-sighted revenge. Within a year, the Jenkins-ite right had broken away to form the SDP. Healey stayed on under Neil Kinnock as shadow foreign secretary until 1987, retiring to the Lords (“the house of the living dead” in Healey-speak) only in 1992. Helping to keep the party together in its acute moment of peril had been his greatest achievement, Healey would later tell visitors. But he would also say that his combination of popularity and authority could have beaten Thatcher in 1983, when Foot “the unity candidate” was thrashed. Some leftwingers came to agree with him.

In old age, Denis Healey wrote successful books, articles and lectures for large fees. His puritanism steered Healey away from the City, but his habit of razor-blading and hoarding newspaper clippings never left him. In 1994 he was the first major figure openly to endorse Tony Blair as Labour’s next leader within hours of John Smith’s death, though after the 2003 invasion of Iraq – which the ex-Anzio beach master deplored – Healey urged his replacement by Gordon Brown. Always pro-UN, he argued that Iraq should become a UN protectorate. When Tony Benn died in 2013 Healey was virtually the only surviving Labour contemporary to say what a destructive figure he had been.

Healey’s bluntness, his willingness to change his mind if the facts changed, had survived the decades too, as did his anarchic sense of fun. He even confessed to embarrassment over those eyebrows. “I shaved them off once, but my trousers fell down, so I had to let them grow again.”