Perhaps the oddest claim about the legacy of former Prime Minister Margaret Thatcher, who died on Monday at the age of eighty-seven, is, in the words of the Washington Post, that she “helped invent ice cream as we know it.” Soft-serve, specifically. Almost as odd is how frequently versions of the claim—which range from the baroque (“Margaret Thatcher, Baroness of Ice Cream”) to the purely declarative (“Margaret Thatcher Helped Invent Soft-Serve Ice Cream”) to the cautiously arresting (“Margaret Thatcher May Have Helped Invent Soft-Serve Ice Cream,” emphasis mine)—have proliferated online in the hours since her death. The frozen-dessert origin myth goes like this: shortly after graduating from Oxford in 1947 with a degree in chemistry, Margaret Roberts, the future Mrs. Thatcher, worked briefly at the food conglomerate J. Lyons & Company, where she helped devise a method for whipping extra air into ice cream that laid the foundation for modern soft-serve. The innovation spread thanks to Mr. Whippy, a chain of British ice-cream trucks that paved the way for today’s hawkers of towering cones pierced with Cadbury Flake bars, and became popular worldwide.

There is, of course, a certain appeal to this possible lighter side of the woman The Atlantic has christened the “Iron Lady of Soft Serve.” But this Thatcher-as-Wonka narrative, like most origin myths, resides somewhere in the hazy borderlands between simplification and legend, telling us more about memory and politics than about where soft-serve actually came from.

For starters, most sources agree that the soft-serve industry arose in the United States, not Britain, and that it preceded Thatcher’s arrival at J. Lyons by about a decade. In 2008, Marian Burros offered a version of the conventional narrative in the Times:

Either J. F. McCullough or Tom Carvel deserves credit as the first soft-serve maker. Mr. McCullough made soft serve in 1938 in Moline, Ill. One August day, he offered it at a friend’s ice cream shop in Kankakee, Ill., and 1,600 people paid 10 cents for all they could eat of his newfangled treat.… Mr. Carvel appears to have stumbled on soft serve about the same time. When his truck carrying ice cream broke down in Hartsdale, N.Y., he sold it from the truck over two days as it softened.

Sam Dean, blogging for Bon Appétit about the Thatcher-soft-serve connection, suggests that this early soft-serve was more like proto-soft-serve, since “it wasn’t the fluffy, creamy stuff you’d expect to get from a Mr. Softee today.” This raises an intriguing ontological question—if ice cream is soft, and looks like soft-serve, is it, in fact, soft-serve?—but also raises further red flags about Thatcher’s bona fides, condemning her, at best, to be a lesser figure in the sort of Talmudic quarrels that have characterized disputes about the origins of the hamburger and other iconic foods. It also doesn’t hurt that McCullough and Carvel founded Dairy Queen and Carvel (and did so before Thatcher arrived at J. Lyons), whereas Thatcher merely went on to be Prime Minister.

Furthermore, the history of the British soft-serve industry in particular does not reinforce the notion that the soft-serve technology developed by J. Lyons & Company, much less by Thatcher, laid the groundwork for Mr. Whippy’s cones. As in the United States, in Britain multiple entities pioneered soft-serve simultaneously. One was J. Lyons—but, according to Steve Tillyer, who is almost certainly the most avid amateur chronicler of midcentury British soft-serve, with several books on the subject to his name, J. Lyons entered the industry by partnering with the American ice-cream-truck brand Mister Softee and opening local franchises using that company’s American machines. “The story of soft ice cream in Britain,” Tillyer writes, “started in the United States.”

By 1959, Tillyer continues, J. Lyons was “in the vanguard of the new soft ice cream revolution and well ahead of Walls”—T. Wall & Sons, a subsidiary of Unilever—“who had to purchase the Mr. Whippy organisation in order to catch up.” Lyons-owned Softee and Walls-owned Whippy were rivals, the Coke and Pepsi of British soft-serve. Reached by phone at the B. and B. he operates in Northamptonshire, Tillyer told me that Softee and Whippy evolved separately from one another, and that Whippy was in fact founded because its proprietor failed to secure rights to the Softee brand. Even if Thatcher had somehow devised aeration techniques at Lyons, the company didn’t turn over its secrets to Whippy. Tillyer has serious doubts about the Thatcher myth. “I did quite a bit of research,” he said, “and one of the problems is that other people have written stuff where I haven’t been able to substantiate what they’ve written.” Tillyer also notes that Lyons’s primary goal when Thatcher worked there was to invent a soft-serve recipe that was compatible with Softee’s American machines—a recipe that was still much denser than modern variants. The real aeration breakthroughs, he says, occurred when ice-cream-machine manufacturers themselves—often American or Italian—introduced equipment, during the sixties, that included mechanized air pumps.

What, then, accounts for the popularity of the Thatcher soft-serve origin myth? One possibility is that, given the embarrassingly New World pedigree of soft ice cream, anointing Thatcher as queen of soft-serve provided Britons with a less problematic, and more nationalistic, account of where those cones they spear with Flake bars come from. (A similar patriotic impulse may lie behind the widespread notion that Thomas Jefferson introduced vanilla ice cream to America.) But an article published in the Notes and Records of the Royal Society in 2011—and linked to by The Atlantic in its soft-serve post—hints at a more political explanation: “An oft-told anecdote in British left circles associates Thatcher with the invention of soft ice cream, which added air, lowered quality and raised profits.” In other words, it wasn’t Thatcher’s supporters who spread the soft-serve myth; it was the left-wingers, who saw in it a suitable metaphor for her policies.

Photograph, of Margaret Thatcher, by Andrew Kiggins/Daily Mail/Rex USA.