Burger King has launched its first plant-based burger in the UK - but it is not suitable for vegans and vegetarians.
The soy-based version of its Whopper burger is cooked on the same grill as meat burgers.
The fast food chain says the Rebel Whopper is aimed at those who want to cut meat consumption.
But a spokesperson for the Vegan Society called the launch a "missed opportunity".
Burger King says that the burger "patty" itself is plant-based, but because of how it is cooked it will not be labelled as suitable for vegans or vegetarians.
It will also be served with mayonnaise, unless the customer asks otherwise.
Katie Evans, marketing director for the chain, said the burger was aimed at "flexitarians". She added it wanted the burger to replicate the "flame-grilled taste" as closely as possible.
Burger King did confirm, though, that its vegetarian bean burger and its vegetarian option on the children's menu are cooked separately.
Sam Calvert, head of communications at the Vegan Society, said that not making the new burger fully vegan "seems a missed opportunity".
She added that vegan mayonnaise was "readily available" and used by other well-known chains, which would also make the burger suitable for some religious groups that avoid eating certain animals and eggs.
'Jumping on the bandwagon'
The Rebel Whopper launch on Monday also saw a backlash on social media. One Twitter user called it "a case of big corporations jumping on the bandwagon of a trend".
Lifestyle blogger Donna Wishart criticised Burger King for failing to deliver "actual vegan products", when other fast food companies do so.
And it’s served with mayonnaise with eggs in. When every other fast food company is delivering actual vegan products it’s such a shame Burger King can’t be bothered to do the same.— Donna Wishart - What the Redhead said (@genuineplacebo) January 6, 2020
However, Toni Vernelli, international head of communications and marketing at Veganuary, dismissed claims that Burger King was trying to "capitalise on the vegan pound".
She said that "increasing the availability of plant-based options" was the best way to encourage the reduction of meat consumption.
"Don't let perfection be the enemy of good," she said.
The Vegan Society describes veganism as a "lifestyle" that avoids all animal foods such as meat, dairy, eggs and honey, as well as animal-based products like leather.
600,000According to a Vegan Society survey of 2,000 people in 2018
£740mEstimated sales of meat-free foods in 2018
87%Most Veganuary participants in 2019 were female
According to the latest research by the Vegan Society, conducted in 2018, there are about 600,000 vegans in Great Britain.
Flexitarianism, part-time vegetarianism or veganism, is becoming more popular.
In 2020, at least 300,000 people pledged to go vegan for the first month of the year, under the Veganuary campaign, the organisation said.
Interest in vegan and vegetarian products shows no sign of slowing down. This January, other well-known food chains have launched meat substitutions for popular products.
Bakery Greggs announced a vegan "steak bake" after the success of its vegan sausage roll last year, while coffee chain Costa said it would offer a "vegan ham and cheese" toastie.