A FATHER and son remain convinced a shark attacked their boat on a fishing trip - despite being told last night it was probably a porpoise.

Philip Walker, 43, took a picture of a dorsal fin ripping through the water straight at them.

Seconds after the photograph was taken he and his son David, 13, felt a huge impact knock their boat sideways in the water and the frightened pair clung on in terror.

The creature circled the vessel several times and bumped their boat again, before disappearing out to sea off North Shields, North Tyneside.

Mr Walker, from Cowgate, Newcastle, said: "It must have been 12 or 13ft long and could have been about 250 kilos and when it hit the boat the bairn got a bit of a fright. I wondered if it might be a dolphin, but the pictures show it was definitely a shark."

But Zahra d'Aronville, the display supervisor of the Blue Reef Aquarium, at Tynemouth, said: "I don't think it's a shark because it's breaching the surface of the water and that is more characteristic of a mammal such as a porpoise, a dolphin or a minky whale.

"Sharks don't come to the surface very much at all, although after watching Jaws that's what people do think."

Last night, Mr Walker continued to insist he had seen a shark.

"To be honest, I'm frightened because a lot of people use that area around North Shields and Tynemouth now, and there is a shark there," he said.