The origin of the once-popular landline phones has been a mystery ever since the first shards started appearing on the Finistère sands near Brittany, France 35 years ago.

That is until a group of anti-litter campaigners joined forces with a local farmer who unlocked the secret source of the mysterious orange plastic phones.

In 2019, a farmer on the Iroise coast in Brittany led the Ar Vilantsou anti-litter group to a cave that was only accessible during low tide.

There, lodged between the rocks, the group found a long-forgotten shipping container that had run aground during the 1980s.

Its hinges crushed long ago, leaving its precious cargo - the novelty Garfield phones - exposed to the whims of the rising tide.

"This is the first time in our lives that we've seen that," Claire Simonin-Le Meur told France Info reporters.

Ms Simonin-Le Meur is the president of the Ar Vilantsou beach clean-up crew and has been scouring the beach for years in search of the origins of the phones.

"We're dealing with quite an interesting story," Ms Simonin-Le Meur said.

"When we're meeting schoolchildren, and we do clean-ups with them, as soon as we speak about Garfield, the issue of marine trash, which is our main concern, it starts exciting people.

"It's really an issue which we feel strongly about."

But with the container irretrievably stuck in the cave, a new challenge presents itself to the environmentalist group.

How many more phones the container is carrying is unknown, so it's expected that the plastic shards will continue escaping into the waterways, washing up onto the once-pristine shoreline.

Being mostly plastic, the novelty phones are not expected to decompose in a lifetime.

So, until the container can be accessed and retrieved, Ar Viltansou and the residents of Finistère say they are committed to harvesting the remains of the lasagna-loving cartoon feline from the sands.