‘Spanish’ beer Madrí—brewed entirely in the U.K. and owned by $10.6 billion giant Molson Coors—accused of dishonesty by Spanish brewer Estrella

Since 2020, British drinkers have flocked to the exotic-sounding Madrí beer in search of a taste of Spain in U.K. pubs. One person unlikely to be toasting the drink is the boss of rival Estrella, who is sick of the British-brewed lager stealing his market share.

Madrí was created as a collaboration between owner Molson Coors and Spanish brewery La Sagra. It has gone on to huge success, recently topping £100 million in U.K. supermarket sales.

Naturally, Madrí—spelled to match the traditional way to pronounce Spain’s capital Madrid—leans on the European brewer to market the beer. There is no mention of the link to Coors on the brand’s About page, nor the fact that the Canadian American brewing giant has also owned La Sagra itself since 2017.

Instead, the brand dedicates ample space to Madrí’s cover star, the “Chulapo,” a type of local bohemian figure known for their “elaborate style,” Madrí says.

It all forms part of a story that is meant to entice British consumers who have become partial to higher-percentage “world beers” in recent years.

However, the lager, which launched in pubs three years ago and has become a leading brand in the country, is brewed entirely in the U.K., raising questions about its heritage and how it is marketed.

Those unsympathetic to Coors don’t believe that’s by accident. One of those voices is Estrella boss Aitor de Artaza, who has his own interest in pointing out Madrí’s slightly awkward origin story.

Speaking to the Telegraph, the boss of Estrella, which is owned by Spanish group S.A. Damm, didn’t mince his words after watching consumers opt for its new rival.

“There is a lack of transparency because they use a big famous city in Spain, but they don’t produce here. This is confusing for the consumer,” de Artaza said.

“They did a very nice job in terms of marketing, that’s for sure. But it’s a little bit tricky because people think they are drinking a Spanish beer but it’s not. They are not very clear and not, to my point of view, very honest.”

In a statement to Fortune, Molson Coors premium brands director Karen Albert highlighted that Madrí was a collaboration between the group and Madrid-based brewer La Sagra.

Albert added that brewing in the U.K. allowed it to deliver efficiently and respond to demand.

“Brewing Madrí Excepcional here in the U.K. enables us to deliver efficiently, quickly respond to demand, and, crucially, to make our beers more sustainably,” she said.

Rule of origin

Madrí Excepcional is one of several drinks brands owned by Molson Coors, a $10.6 billion multinational based in Chicago. The company also owns brands including Coors Light, Carling, and Grolsch.

Coors has a history of marketing its beers with a geographically ambiguous origin story. The brewer developed Blue Moon, a “Belgian-style wheat beer” that was first developed in Denver.

More broadly, big international brewers have increasingly opted to brew in the U.K., at least for British customers, including Italy’s Birra Moretti and Australia’s Fosters.

It’s unclear how many drinkers are aware that Madrí’s identity isn’t all that it seems. As the European Football Championship kicks off and U.K. drinkers flock to pubs, Estrella’s boss will hope it might inspire a bit of pre-game chat.

This story was originally featured on Fortune.com