P&O Ferries has considered banning pugs from its vessels after the tragic death of four-year-old Merlin last month.

The much-loved pug was found dead in his owner’s car on-board the Spirit of France crossing from Calais to Dover and is said to have died from heat exhaustion after temperatures soared to more than 30 degrees.

The cross-Channel operator insists the ventilation was at the correct setting and has since voiced concerns over carrying breeds like pugs, who can have respiratory problems.

Spokesman for P&O Brian Rees said: “One reaction here, perhaps an understandable knee-jerk reaction, was that we adopt the policy that a lot of major airlines follow.

'Many airlines simply refuse to carry brachycephalic breeds such as pugs.' - Brian Rees, P&O.

“This is because these dogs are developed primarily for cosmetic looks, specifically a deformed upper jaw which is compressed to such an extent that it causes many animals of this type to suffer from physical difficulties.”

"Many airlines simply refuse to carry brachycephalic breeds such as pugs."

A brachycephalic dog is one that has a shortened bone structure and leads to respiratory distress.

P&O also said that in the grand scheme of things this type of incident is a rarity and on that same crossing,the Spirit of France carried 21 other dogs.

The incident sparked an immediate online petition, where thousands of people have appealed for the ferry firm to consider having dogs on passenger decks.

Mr Rees continued: “Some people have jumped to the conclusion that we must need a fundamental review of the way we carry dogs because of this incident. We don’t see it like that.

“We just could not carry hundreds of dogs that day, and thousands upon thousands of dogs without incident, if our process was not fundamentally sound.

“The Animal Health and Veterinary Laboratories Agency’s Welfare in Transport team issued an advisory to ferry companies after this incident.

“There’s nothing in the advisory that we don’t already embrace.”