Looming over any discussion of politics and drinking is the figure of Winston Spencer Churchill. Not only did he lead his nation to victory over the teetotal Adolf Hitler in the greatest war in history, but he did so while consuming magnificent amounts of whisky, champagne, and brandy. He is our standard-bearer and testament that, contrary to the credo of our present nanny state, a fondness for a strong drink or three is not a sign of moral turpitude.

Churchill bestrides Ben Wright’s Order, Order!: The Rise and Fall of Political Drinking like a colossus: carving up Europe at Yalta over martinis with fdr and vodka with Stalin, describing Prohibition as an “affront to the whole history of mankind,” and, quite unexpectedly, trying to ban barmaids from pubs—it was once thought a woman’s presence encouraged over-indulgence and under-productivity amongst the working classes. A whisky and soda was always close to hand while Churchill worked, but it was at mealtimes that the serious drinking took place. Churchill’s secretary Jock Colville recorded a typical wartime dinner in his diaries in September 1944: “oysters, consommé, turbot, roast Turkey, ice with cantaloupe melon, Stilton cheese and a great variety of fruit, petit fours etc, the whole washed down by champagne (Mumm 1929) and a very remarkable Liebfraumilch, followed by some 1870 brandy.”

Do not imagine it was the pressures of office that drove Churchill to dash for the drinks tray. Shipping out as a reporter to cover the Boer War in 1899, he packed his pith helmet, eighteen bottles of scotch, and almost forty of wine. On New Year’s Eve 1935, when Churchill was deep in the political wilderness, the newspaper magnate Lord Rothermere bet him that he could not give up alcohol for the coming year; the future savior of the West refused on the grounds that “life would not be worth living.”

Order, Order! suggests that you could have found a solid majority to support this motion in any Parliament before the Age of Cameron. A political reporter for the bbc, Mr. Wright is comfortably at home in Westminster, and the heart of his book is a lively account of its many drinking holes and of six decidedly non-abstemious prime ministers of the United Kingdom: Robert Walpole, William Pitt the Younger, H. H. Asquith, Churchill, Harold Wilson, and Margaret Thatcher. (Tony Blair gets an interesting portrait, too, with his memoir’s admission that alcohol became a “prop” as the years in office took their toll.)

MPs can slake a thirst more easily than their constituents since the bars of the Houses of Parliament are exempt from the country’s licensing laws and set their own operating hours. Before the 2010 MP expenses scandal, they also sold the stuff at cut-rate prices. Even today, the government spends £750,000 subsidizing alcoholic beverages for the people’s representatives and their staffs. The Tories traditionally favored the Smoking Room, the only bar reserved for sitting MPs. This wood-paneled and leather-chair-bedecked clubroom was long the barometer of the conservative mood, says David Davis, the Brexit Secretary in the present government. In his memoirs, the long-serving conservative backbencher Julian Critchley describes relaxing with a book and a drink in the Smoking Room in 1959 and being admonished by an elderly Tory, “Young man, it does not do to appear clever: advancement in this man’s party is due entirely to alcoholic stupidity.”

Labour held court in the wonderfully named Strangers’ Bar, so called as it’s the only place where MPs can entertain the public, though strict rules mean no matter who is actually paying

the MP must hand over the money. The Pugin Room is Parliament’s most sumptuous bar and a source of contention between the Lords and the Commons as the former traded it away in 1906 for a committee room and have been angling for its return ever since. There’s a “shiny little nook besides the Lords cafeteria” that serves the upper house’s bracing needs. But, with its bright lights and high pine tables, Mr. Wright reports, it is favored by no one: “like the Chamber it serves, the Lords Bar is of uncertain purpose.” The dens of drinking in Westminster also include the long Thames-side terrace, the pub-like Sports and Social Club, and an official press bar that, like anything with such an express purpose, is shunned by its constituents.

Mr. Wright serves up round after round of topping anecdote, from Neil Kinnock’s leading the press bar in renditions of “Land of My Fathers” and various rugby songs to Robert Maxwell’s selling off the grand vintages of the Commons cellar—skimming the best off for himself at “bargain-basement prices.” The Labour grandee

George Brown is a star here. His great gift for intoxicated gaffe gave rise to the finest press euphemism for being drunk: “tired and emotional.” More genial by far was the ultimate champagne socialist, Roy Jenkins, who asked for a case of claret as his luxury on Desert Island Discs in 1989. Mr. Wright notes that this “supply would have run dry by lunch on the second day, but Jenkins could have used the empty bottles to send out urgent messages for more.”

Such morsels are the book’s strength and its fun. When Mr. Wright goes abroad he is a tourist, giving us Wikipedia-lite accounts of Australian PMs indulging too broadly and a Brezhnev or Yeltsin knocking back the Smirnov. His brief foray into U.S. politics doesn’t suggest wide reading. And he is prone to little slips in his facts. The litigious Koch brother is William, not Edward (who was an unrelated mayor of New York City). It was not at “New York’s Four Seasons hotel” that the wine merchant William Sokolin accidentally smashed a bottle of 1787 Château Margaux he was trying to sell for $500,000 but at the city’s famed Four Seasons restaurant. The Manhattan strip club that the future Australian prime minister Kevin Rudd had “no recollection” of entering or eventually being thrown out of in 2003 is Scores, not Storms.

Mr. Wright is happiest in Westminster where the bits of memoir he mixes with interviews strike a perfect note of refreshment. And he even offers the suggestive nugget that drink can be blamed for the rise of Jeremy Corbyn to the leadership of the Labour Party. The gdr nostalgic is himself, of course, a teetotaler (and a vegetarian). But on February 22, 2012, the Labour MP Eric Joyce was drunk enough in the Strangers’ Bar to head-butt a conservative backbencher, punch one of the Labour whips, and assault two Labour councilors before being subdued. He avoided a prison sentence but was expelled from the party. His replacement became a source of contention when Unite, England’s largest trade union, tried to rig the selection process in favor of its preferred candidate. Furor over this incident led to the adoption of new rules aiming, as Mr. Wright says, “to broaden the membership base of the party and appear to diminish trade union influence.” The revised system allowed people to sign up for the party and vote in any leadership contest. When over 100,000 people did just this in the summer of 2015, Mr. Corbyn became the Labour party leader. We might think of this as the mother of all hangovers.