Stunning footage has emerged of a great white shark smashing through a diving cage and escaping through the top while a diver was still inside.

The breathtaking video was captured off the coast of Guadalupe Island, in Mexico, by a Californian man who documents the his adventures with his two sons.

The video posted this week shows the shark squeezing its way into the cage and thrashing around for a heart-stopping time in the cramped space while the diver was stuck inside.

“What might appear to be an aggressive great white shark trying to attack the cage, this is not the case,” the cameraman wrote on his YouTube account, Gabe and Garrett.

When it becomes apparent the shark has breached the cage, one of the crew throws open the roof of the cage and stands back as the shark thrashes around and finally finds its way out of the top of the cage.

“Is somebody in the cage? Somebody’s in the cage,” he shouts.

Moments later the diver emerges badly shaken, but, astonishingly, unhurt.

“The diver is a very experienced dive master, remained calm, and when the shark thrashed back outside the cage, the diver calmly swam back up and climbed out completely uninjured,” the man wrote.

See the stunning footage