LONDON • The croissant, the buttery breakfast pastry, means "crescent" in French. But do not tell that to the British.

Tesco, Britain's largest supermarket chain and a bellwether of sorts for popular tastes, last Friday stopped selling the traditional curved pastry, selling instead only straight ones. It offered a decidedly British rationale: It is easier to spread jam on the straight variety.

That spurred no shortage of dismay on both sides of the English Channel.

"Is this a foretaste of Brexit?" French newspaper 20 Minutes asked, referring to the possibility that British voters might decide in a referendum to leave the European Union. It added that it appeared that Tesco's move was not done "to antagonise the French (well, not solely)".

An editorial in The Daily Telegraph, a conservative British newspaper, noted that the virtue of the traditional French croissant was its foreignness.

"They must not be sliced in two, like buns to be buttered," it observed. "They must be torn, and each morsel eaten with jam, even alien apricot jam, if wanted."

It added: "Otherwise nature is outraged, floods will again sweep the land and murrains strike our cattle. Or we could just stick with toast."

But Tesco's croissant buyer Harry Jones cited what he called the "spreadability factor". He said that sales of crescent-shaped croissants had been falling.

"The majority of shoppers find it easier to spread jam, or their preferred filling, on a straighter shape with a single sweeping motion," he said in a statement.

"With the crescent-shaped croissants, it's more fiddly, and most people can take up to three attempts to achieve perfect coverage, which increases the potential for accidents involving sticky fingers and tables."

But in a week when Prime Minister David Cameron was in Brussels trying to wring concessions from fellow European Union leaders over Britain's future in the 28-member bloc, The Times of London called the timing of the "major culinary snub" to the quintessentially French pastry "indelicate to say the least".

Among the experts, divisions run deep on the question of whether croissants should be curly or straight.

Benjamin Turquier, who was voted the best butter-croissant maker in Paris and the surrounding Ile-de-France region by the Paris- based association of professional bakers, said he baked only straight croissants because they were easier to roll and fit neatly in a baking tray. "I can understand the importance of symbolism and tradition, but straight croissants are more practical to make," he said on the telephone from Paris.

Richard Bertinet, whose Bertinet bakeries in Bath are renowned for their French bread and pastries, said he sold only straight croissants.

"A real croissant should be straight," he said. "In France when I was working as a baker's apprentice, I learnt the cheap croissant should be curved and the straight ones were always made with butter. So the parents would have a straight croissant and the kids would have a curved croissant."

While the croissant is associated with France, the pastry originated in what is now Austria, as a crescent-shaped roll called a kipferl.

According to Heather Arndt Anderson's Breakfast: A History, the croissant was introduced to France in the late 1830s, when an Austrian artillery officer named August Zang founded a bakery that sold kipferl. The rolls caught on and the croissant was born, along with a name befitting its distinctive shape.

Some observers on Twitter expressed their disbelief that British jam-spreaders were unable to navigate a traditional croissant's curved edges.

"Utterly preposterous. Croissants are curved traditionally. Must be another EU directive!" wrote Timothy William of Belfast, Northern Ireland. Others mocked what they saw as a marketing tactic by the retail chain.

Meanwhile, Jean-Christophe Novelli, the former personal chef to the French Rothschilds, who now runs a cookery school in Hertfordshire that has been hailed as one of the world's best, said the French would "absolutely not" spread butter or jam on their croissants.

"A croissant is something that you dip into a bowl of chocolate or coffee," he said. "But never in my whole life have I met someone from France who eats a croissant with jam."

NEW YORK TIMES, THE GUARDIAN