A ferry company has defended itself against allegations of animal cruelty after a family's pet dog died on a Channel crossing.

Current rules do not allow pets to be taken out of vehicles on crossings, and neither can owners sit with them.

On a hot day last week, the Wallace family from Brookwood, Surrey, were travelling with their sons and three dogs, including four-year-old pug Merlin, on a P&O Ferries' Calais to Dover crossing.

On arrival at Dover, the Wallaces found Merlin unconscious, and the animal died despite efforts to revive him.

On Twitter, P&O have been accused of cruelty to animals.

P&O Ferries spokesman Chris Laming said today: "We are reviewing our policy concerning dogs. But this particular dog was in a car with two other dogs which were fine, and there were a total of 20 dogs on that crossing.

"We also carried more than 250 dogs last week and the carrying of pets on board has worked well since it was introduced in 2000."

A post on the company's Facebook page said: "Many airlines refuse to transport certain breeds of dogs, notably pugs, bulldogs and other brachycephalic breeds, due to the respiratory issues from which these animals are prone to suffer.

"P&O Ferries, which carries more than 50,000 pet dogs a year of all breeds, is reluctant to stop offering a service to the owners of certain breeds, believing that owners are best placed to judge the suitability of conditions when transporting their animals."