A lifetime later, it seems almost unimaginable that the writer and historian John Grigg, who has died at the age of 77, was once regarded as a dangerous radical. Denounced more than 40 years ago as a crypto-republican and subverter of established order, he seemed by the 21st century - as an Englishman, an Anglican and a Tory - to be a survival from some remote period, with his courtesy, decency and high principle.
Maybe he himself recognised that he was an anachronistic figure, and turned, in his later decades, from public controversy to history, above all his life of David Lloyd George, which is one of the finest political biographies of our time.
John was the son of Edward Grigg, a Times journalist associated with the imperialist circle of Joseph Chamberlain and Lord Milner, a soldier, Conservative MP, governor of Kenya, and member of Churchill's wartime government, who was created first Baron Altrincham in 1945.
After Eton, the young man followed his father into the Grenadier Guards (1944-47), and to New College, Oxford, where he won the Gladstone Memorial Prize. In paternal footsteps once more, he aspired to journalism and politics, editing the English And National Review (1954-60) as his father had done, and standing, unsuccessfully, as Conservative candidate for Oldham West at the 1951 and 1955 general elections.
He was a conspicuously liberal Tory at a time when that phrase did not seem a contradiction in terms, though, even then, his distaste for his party's hanging and flogging brigade - and for late-imperial adventures like Suez - made him distrusted by many Conservatives.
In 1955, Grigg's father died, and he succeeded as Lord Altrincham, the name by which he was known for the next eight years. A resolute critic of the hereditary House of Lords, who still hoped to become an MP, in 1963 he reverted to John Grigg by following Lord Stansgate, who had disclaimed his peerage to become Anthony Wedgwood (subsequently Tony) Benn once more.
He had already acquired national notoriety in 1957 by writing an article criticising the Queen - he called the court "complacent" and "out of touch", and deplored the way a monarchy that should have been truly national and above class divisions was, in practice, intimately associated with the upper classes. There was an uproar: Altrincham was dropped by the BBC from Any Questions, the Duke of Argyll said that he should be hanged, drawn and quartered, and, after he had gently reiterated his strictures in a television interview with Robin Day, he was assaulted in the street by an angry royalist.
What seems astonishing now is how much rage Grigg's reflections provoked, and how mild they were. As he said in the programme The Real Queen, shown last night on Channel 4, by the 1950s the idea had somehow crept in "that you couldn't say a word against the royal family, let alone the Queen". And yet, he had quite obviously spoken not as a revolutionist but as an enlightened Tory, and as a strong believer in constitutional monarchy. He had no wish to be disloyal, still less unchivalrous; and much of what he sug gested later came to pass.
Even so, Grigg contined to lament 20 years ago, at the 30th anniversary of the Queen's accession, the way that her entourage "should still be unrepresentative not only of the Comonwealth, but even of the United Kingdom. To put it bluntly, there are no black or brown faces in prominent places at court, and this contradicts what the monarchy ostensibly stands for".
The Commonwealth was another of the causes to which Grigg gave his heart. He hated any form of racism, and advocated a strenuous multiracial policy for the Commonwealth, even if it meant (as it did) the departure of apartheid South Africa. He knew and loved India, and suggested that Gandhi was a more appropriate patron saint for the Commonwealth than St George.
From 1960-70, Grigg wrote a column in the Guardian, as he did in 1986-93 for the Times, and he was, for a time, political columnist of the Spectator. But he was, in truth, not a particularly exciting newspaper writer, and his fastidiousness and modesty meant that workaday journalism was never quite his metier.
In any case, he was increasingly disillusioned by politics, or at least by the Conservatives. Throughout the 1970s, he continued to oppose attempts to reintroduce the death penalty, but, in the end, gave up hopes of entering parliament, and, in 1982, left the Tories for the SDP. Apart from a little volume, Two Anglican Essays (1958), he was in his 40s before he published a book. When he did so, he soon emerged as one of the best historians of his time.
There was a 1980 biography of the formidable, and not very lovable, Nancy Astor, the first woman to sit in parliament, and 1943: The Victory That Never Was (also 1980), a fascinating exercise in counter-factual history, which argued - convincingly - that Churchill had held back too long from the invasion of northern Europe, which should have taken place a year earlier than 1944, and ended the war sooner.
Grigg also held that the first of the two world wars had been "the nobler war". In defiance of the prevailing liberal view of the interwar years - that Germany had been more sinned against than sinning - he argued that Wilhelmine Germany had been aggressive, militaristic, anti-democratic and bent on the domination of Europe, and had indeed been responsible for the war that began in 1914. This is now something like the accepted view among historians of the period.
As for the senseless slaughter of the trenches, those who died were, at any rate, soldiers. Whereas in the "people's war" of 1939-45, it was the people who suffered; what made that war so distinctive was not the millions of combatants who died, but the tens of millions of civilians. Grigg abhorred the waging of war on women and childen, notably in the British terror-bombing campaign of Germany.
The masterpiece for which he will be remembered, however, is his life of the man whom AJP Taylor called the greatest prime minister of the 20th century. Three volumes have been published: The Young Lloyd George (1973), Lloyd George: The People's Champion (1978, when it won the Whitbread Award for biography), and Lloyd George, From Peace To War 1912-1916 (1983, winning the Wolfson prize).
Biographer and subject might have seemed an unlikely pairing. Grigg was the antithesis of the fiery, word-intoxicated radical who stormed across the political stage and then became a great war leader. But he showed a remarkable sympathy, and even affinity, for the Welsh wizard, despite the fact that their domestic personalities were very different.
Grigg, who had once skittishly said that "autobigraphy is now as common as adultery and scarcely less reprehensible", was, in public and private life, a truly virtuous man, whose virtue was occasionally just this side of priggishness. While recognising Lloyd George's political stature, he might easily have been shocked by his ceaseless lechery; in fact, he was relaxed and uncensorious on the subject, only - and justly - deploring the unconscious cruelty of the male philanderer who doesn't recognise that sexual attachments may mean more to the women he seduces than to himself.
He was more sharply critical - and with reason - of Lloyd George's financial adventures, reckless, unscrupulous and, on occasion, plain dishonest. Even then, he could not help warming to the man's humour, and leonine vitality.
In later years, Grigg was stricken by cancer, and went through the usual cycle of treatment, remission, and recurrence. Sadly, this affected his work, but, before his death, he had nevertheless returned to Lloyd George and the years of his premiership in 1916-22. It is to be hoped that some further volume of this grand work may yet appear.
In 1958, Grigg married Patricia Campbell, who survives him with their two sons.
· John Edward Poynder Grigg, writer and historian, born April 15 1924; died December 31 2001