US fast-food giant Burger King on Tuesday launched its meatless burger in Europe, hoping to capture a substantial slice of a growing market.

The vegetarian version of its prime “Whopper” hamburger is being added to the menu in 25 countries and 2,500 restaurants after testing in the United States and Sweden.

“It’s the biggest production launch ever done in Europe. We see the potential in the future that this is a growing category,” company president David Shear told AFP.

The new meatless sandwich is to be launched in Britain at a later date, possibly around the start of next year, the firm said.

Burger King, which is best known for flame-grilled patties, said with the new product it was now the biggest European fast-food restaurant chain offering a veggie burger.

The company said the vegetarian product had boosted sales of traditional burgers in the United States, as it attracted new customers who normally did not patronise fast-food outlets.

Some critics noted however that if the same cooking grills were used for meat and chicken products, strict vegetarians would shun the new offering.