A rare Lego piece that fell into the sea in 1997 has been found by a 13-year-old boy in Cornwall.

Liutauras Cemolonskas had been hoping to find a "holy grail" plastic octopus for two years in his hunt for pieces of Lego that famously fell into the sea in 1997 when a cargo ship encountered a storm. Among the Lego pieces that fell into the sea were 352,000 pairs of flippers, 97,500 scuba tanks, and 92,400 swords - but octopuses are the most prized objects as only 4,200 were onboard.

Liutauras, who found it on a beach in Marazion, regularly goes down to the local beaches with his parents and has amassed 789 Lego pieces over the course of two years, as well as numerous fossils. "We've been looking for that octopus for two years, it's not easy to find," his father Vytautas Cemolonskas, 36, said.

"We were not expecting to find it at all because it's very rare." Beachcomber Tracey Williams is behind the Lego Lost At Sea project, which has spent years finding the plastic pieces since they spilled into the ocean. She said she found one octopus in 1997 and didn't recover another one for 18 years.

"I think there's something quite magical about the octopuses," she said. "They're often seen as the holy grail of finds from that shipping container." Read more:Lego halts commercial operations in Russia indefinitelyWhat Lego tells us about the immense difficulties of going green In what Ms Williams calls a "quite exciting" development, a second Lego octopus was found just two days after Liutauras's discovery, this time in Porthleven.

"I think that's because we had a very high spring tide coupled with strong onshore winds and when the two collide, the waves eat into the dunes that then release a lot of the plastic that has washed up," she explained. Ms Williams has been working on research related to the cargo spill and wrote a book, called Adrift: The Curious Tale of The Lego Lost At Sea.

"I'm recording where it all washes up so we're working on a map that will form part of a scientific paper to show how far plastic from a cargo spill drifts and what happens to it over time," she said. "What we'd like to find out is whether those containers still exist or whether they've long since rusted away." She added: "I mean, it's intriguing to know what's happened to all the rest of the Lego that we've never seen.

"There are so many cargoes spilled every year, but you very rarely hear what happens to the goods inside and what we know from the Lego story is that 27-year-old plastic that was inside that shipping container is still being found.".