A UK diver who wanted to demonstrate that you don't need to go to the other side of the world to see amazing marine wildlife, experienced an incredible encounter with a huge barrel jellyfish.

Dan Abbott was filming marine life off the British coast near Falmouth, Cornwall on Saturday when he spotted the massive jellyfish.

Dan said he was completely awestruck by the mammoth stinger and snapped a picture of biologist Lizzie Daly, who is the host of BBC Earth, swimming alongside it to demonstrate just how big the specimen was.

The 32-year-old underwater cinematographer from Colchester, Essex, said, "It's the biggest jellyfish I've ever seen, in some ways I was shocked—but not in a negative way, more awestruck."

"It was an incredible animal, we both came out the water completely mind blown from that experience."