More than 5,000 people have signed a petition calling for dogs to be allowed on the passenger decks of ferries after a pet died in a car during a crossing to Dover.

The three-year-old pug had been left in a car during the journey on Friday when temperatures reached more than 30C.

P&O said procedures had been followed correctly - the windows were open and the ship's ventilation was working properly.

The family, who are believed to be moving from Germany to England, were travelling on the Spirit of France which left Calais on Friday at 10.45am and arrived in Dover local time at 11.20am.

When the family returned to their vehicle after the hour-and-a-half journey, three-year-old pug Merlin was dead.

Now a petition has been set up to hold ferry companies to account - as it explains cross-Channel ferries do not allow owners to have their pets with them. Animals must remain in the vehicles.

"It would be an animal rights abuse for a person to leave their pet in their car on land for over an hour, so how can the ferry companies be allowed to make pet owners do this...?" - petition

The petition has been set up by Nina Gadson, who lives in Aldershot, and addressed to Defra and Elizabeth Truss, the new secretary of state for Environment, Food and Rural Affairs.

It read: "A friend's dog died on a cross channel ferry run by P&O due to heat exposure, they came down to their car after the 1.5 hour crossing to find one of their beloved pets dead, this is not an isolated incident.

"Defra says that: Whenever animals are transported, including journeys with pets, the law says that: 'No person shall transport any animal in a way which causes or is likely to cause injury or unnecessary suffering to that animal’, and yet, ferry companies are insisting that pets remain in cars on unventilated car decks.

“It would be an animal rights abuse for a person to leave their pet in their car on land for over an hour, so how can the ferry companies be allowed to make pet owners do this?"

Jade Allan, from Alnwick, said: "This is my sister's dog, and I can't tell you how upset the whole family are.

"He is going to be a massive miss - he was her baby."

However, P&O Ferries has stated that all procedures were followed correctly.

Spokesman Natalie Hardy said: "A passenger was travelling to the UK with three dogs.

"The pets were declared, the car was parked accordingly and in the appropriate place on the car deck with the windows open for ventilation and the ship's ventilation was correctly set.

"However, upon arrival in Dover one of the three dogs had died and could not be revived despite CPR and oxygen.

"This incident was obviously very distressing for the family and the staff who helped try to revive the pet, which was taken away by animal welfare."

To view the petition, click here.