One of the specialities of the historian Norman Stone, who has died aged 78, was character assassination. As a judge of the Fraenkel prize in contemporary history some years ago, he told the astonished members of the jury that they should not award the prize to a historian of Germany whose politics he disliked because she was an East German agent – an allegation that was enough to rule her out of contention even though it was absolutely baseless and undoubtedly defamatory.

Shortly after the death in 1982 of his patron and mentor in Cambridge, EH Carr, the author of a multivolume History of Soviet Russia and influential works on historiography and international relations, Stone published a lengthy assault on his reputation, which included lurid details of his three marriages. When a colleague criticised this “outrageous” diatribe to his face, telling him that Carr “always said you were amoral”, Stone responded: “And he always said you were a bore” (probably an invention, though one cannot know for sure).

At a time when malice and rudeness were highly prized by some rightwing Cambridge dons, Stone outdid them all in the abuse he hurled at anyone he disapproved of, including feminists (“rancid”), Oxford dons (“a dreadful collection of deadbeats, dead wood and has-beens”), students (“smelly and inattentive”), David Cameron and John Major (“transitional nobodies”), Edward Heath (“a flabby-faced coward”) and many more.

Stone was undoubtedly clever. He could write entertainingly and could summarise complex historical circumstances in a few pregnant sentences, gifts which brought him a flourishing career as a journalist and commentator. He was a talented linguist who read and spoke more than half a dozen languages, including Hungarian. Yet his career was also dogged by character flaws that prevented him from fulfilling his early promise as a historian.

Born in Glasgow, Norman was the son of Norman Sr, a fighter pilot who was killed in training just over a year later. Brought up by his mother, Mary (nee Pettigrew), a teacher, he was sent to Glasgow academy on a scholarship from his father’s squadron, flourished academically, and went to Gonville and Caius College, Cambridge, to study modern languages, switching to history shortly after his arrival.

With a good degree in the subject, he embarked on a PhD on the Austro-Hungarian army before 1914, though never completed it, and gained a reputation for brilliance sufficient, along with his linguistic abilities, to obtain a research fellowship at Caius in 1965, and two years later an assistant lectureship in Russian history, moving to Jesus College in 1971 as director of studies in history.

In 1975 he published the book that made his reputation: The Eastern Front 1914-1917, which won him the Wolfson history prize and numerous laudatory reviews. This was a scintillating narrative based on a wide range of sources in several languages, including both Russian and German, admirably succinct and clearly argued. It did a great deal to redress the imbalance of the British historiography of the war, which had up to this point focused almost exclusively on the western front.

It argued powerfully that administrative chaos and poor military and political leadership were more important in causing the Russian defeat than economic weakness. However, its approach was self-confessedly old-fashioned, with its concentration on grand strategy, political and military leaders, to the neglect of the experience and morale of the ordinary soldier, factors that feature strongly in more recent accounts.

During his researches in Vienna, he had met Nicole Aubrey, the niece of the brutal and corrupt Haitian dictator “Papa Doc” Duvalier’s finance minister: they married in 1966 and had two sons. By the time The Eastern Front was published, the marriage was breaking down, and they divorced in 1977.

The resulting financial strain led him to start writing quick potboilers, beginning with a short life of Hitler (1980), a superficial and poorly researched work justly savaged by reviewers, notably Tim Mason, whose exposure of its weaknesses upset Stone considerably despite his own record of rubbishing other historians’ achievements.

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There followed Europe Transformed 1878-1919 (1983), a short volume in the Fontana History of Europe, one of the weakest in an uneven series. His second marriage, to Christine Booker (nee Verity), came in 1982. They had a son, and she died in 2016.

As a teacher Stone could be inspiring, often winning over his pupils with his charm, which on occasion could be quite considerable, but he became increasingly undisciplined, neglecting his duties, and spending increasing amounts of time playing poker and drinking himself into oblivion in Soho.

The Cambridge University history faculty became impatient with his behaviour, but solved the problem of how to deal with him by encouraging him to apply for the professorship of modern history at Oxford, to which he was appointed in 1985 thanks largely to political support from rightwing Oxford dons reinforced by a laudatory reference from Sir Geoffrey Elton, the regius professor at Cambridge.

Stone hated Oxford, which he thought (bizarrely) was full of Marxists and out of touch with the real world. He lambasted the university on a regular basis in his newspaper column while continuing to draw his salary (a sum he frequently dismissed as too miserly to keep him in the style to which he had become accustomed), and excoriating it for refusing an honorary degree to Margaret Thatcher because of the cuts she had imposed on universities (“Why should we feed the hand that bites us?” one don memorably asked).

On the occasions when he did appear in Oxford to do some teaching, Stone became notorious for groping his female students (one of whom is said to have responded with a slap across the face), and annoyed Worcester College by sub-letting his rooms to make a bit of extra money. In 1997 the university finally grasped the nettle and arranged for his departure, though under financial terms that forced it to delay filling his chair until 2006, the year when he would have reached the statutory age of retirement.

Long before this, he had espoused a variety of rightwing political causes, advocating Britain’s departure from the EU, defending the Chilean dictator Augusto Pinochet and supporting Croatia in the Balkan wars. He did some speechwriting for Thatcher and advised her on foreign policy, though she did not listen to his assurances that the reunification of Germany in 1990 was not a danger to European peace. On one occasion he collapsed in front of her, drunk; but she was well known for her indulgence towards alcoholics so long as they supported her politically.

After Oxford, he found a berth in Turkey, where he occupied positions at Bilkent and other universities, resigning from one in Ankara because the authorities tried to stop him drinking.

He devoted some of his remaining energies to the denial of the genocide of Armenians by Turkey in the first world war, but they were fading rapidly, and his last books – short histories of the two world wars (2007 and 2013) and The Atlantic and Its Enemies: A Personal History of the Cold War (2010) – did no justice to his real abilities, mixing worn-out historical clichés with random statements of his own personal views.

His last post was at the Danube Institute, Budapest, and his last book, Hungary: A Short History (2018) praised the country’s authoritarian leader Viktor Orbán among other things for his tough line on immigration.

Knowing that he did little research, never bothered to check his facts and relied on his literary flair to mask his mistakes, the publishers got serious historians to go through the text: one of them sent in a 20-page list of errors, but it was impossible to spot them all and so it was left to reviewers to point out the many further inaccuracies.

There is nothing wrong with historians being provocative so long as their provocations stimulate one to think again about the subjects they deal with. Niall Ferguson on the right would be one good example of fruitful provocation, just as AJP Taylor was on the left. But Stone’s provocations were little more than the voicing of his own personal political prejudices, and so had little or no effect on the way we think about the past.

Journalists often described him as “one of Britain’s leading historians”, but in truth he was nothing of the kind, as any serious member of the profession will tell you. The former prime minister, Heath, was wrong about many things, but he was surely right when he said of Stone during his time in Oxford: “Many parents of Oxford students must be both horrified and disgusted that the higher education of our children should rest in the hands of such a man.”

Stone is survived by his sons.

• Norman Stone, historian, born 8 March 1941; died 19 June 2019

• This article was amended on 26 June 2019. Norman Stone’s first wife, Nicole Aubrey, was the niece rather than the daughter of “Papa Doc” Duvalier’s finance minister.