A surge in extremely young puppies being transported on cross-Channel ferries from Calais to Dover has been highlighted by P&O Ferries.

It is thought European scammers are transporting pups, younger than the legal age of 15 weeks, for hundreds of miles in cramped conditions. They are entering Britain via Dover and are being sold to unsuspecting owners.

Check-in staff in Calais, who noticed pups looked much younger than their documents claimed, flagged up their concerns to bosses in Dover, but due to a flaw in the system, they can not deny boarding if their documents match the microchip on the animal.

P&O press spokesman Brian Rees appeared on a BBC news bulletin on Monday night raising the firm’s concerns

He told the Mercury: “Imagine a situation where check-in staff suspect that what it says on the documentation doesn’t represent what they’re seeing with their own eyes.

“Puppies look so young, too young to be able to meet, for example, vaccination requirements, but the paperwork that has been issued by a vet on the continent says everything is in order.”

P&O staff do not have powers of seizure, but have to contact the authorities. In some instances, the BBC reported, frail puppies go for hours without food and water and die.

Foreign dog breeders make larger profits in Britain than they would in eastern European countries depending on the breed.

The BBC’s report said it is believed the puppies could be carrying diseases like rabies, increasing the potential danger.

Mr Rees continued: “It puts check-in staff in a very difficult situation. The customer has met all the requirements, on the face of it, to bring the dogs into the UK. Do check-in staff tell a customer who has travelled many hundreds of miles that they can’t travel?

“Can check-in staff tell if a puppy is old enough to meet the requirements of the scheme? They’re not vets, so we’ll tip off the authorities to try to make it difficult for people involved in this trade and to try to alert people who may be caught out by it.”