Boss Peter Fankhauser made the announcement in a blog post on Sunday, in which he says: “From next summer, we will no longer sell any animal attractions that keep orcas in captivity.”

Holiday firms have come under pressure in recent years to address their stance on holidays featuring such attractions.

In the post, Fankhauser acknowledges changing public attitudes towards animal welfare, noting 90% of Cook customers are concerned about the issue.

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Cook launched a review of its animal welfare policy 18 months ago to ensure any animal attractions it sells are 100% compliant with Abta’s animal welfare standards.

Besides SeaWorld, the move will see Cook stop selling tickets to Loro Parque in Tenerife, which also houses captive orcas.

While acknowledging both attractions had met its required standards, and had made improvements to welfare, Fankhauser added: “When so many of our customers are so clear in their view, I could not allow our business to ignore them.”

Cook says it has, to date, independently audited 49 animal parks it currently sells against Abta guidelines. Some 29 failed to meet the required threshold and as a result, Cook has withdrawn these from sale.

A SeaWorld spokesperson said: “Millions of UK guests have visited our parks for fun, education and to help contribute to the protection of marine animals and their habitats.

“They have seen first-hand the incredible care we provide all of our animals and learned about how we are protecting and saving species in the wild.

"Although we have ended breeding for orcas, the current animals in our care will be with us and our visitors for many years to come.”