One of the world's top big wave surfers believes he has found two spots off Ireland which could produce waves 120ft high.

Al Mennie, who has surfed some of the most extreme conditions on the planet, said he is waiting for the perfect conditions to surf what he believes is the largest swell on earth.

"This is my mission. The good days are few and far between - 90% of the swells are unrideable and we'd reckon that only two days each year are rideable," he said. "We've been out and ridden them. They weren't enormous but we are waiting for the right conditions."

Portrush-based Mr Mennie and his right-hand man Andrew Cotton, from Devon, refuse to disclose the exact locations of the waves due to the increasing number of inexperienced surfers trying to make a name for themselves on virtually unrideable waves.

One wave is off the west coast of Donegal and the other off Co Antrim. Both crash down on rocky reefs about the size of a tennis court and Mr Mennie claims the water could be as shallow as five feet when the waves are sucked up.

"One of the biggest concerns we would have is that someone inexperienced would turn up and try to get fame and glory," he said.

"Because of the very specific bottom contours on the seabed and the weather, that's what makes these waves. We have to understand how the whole place works for safety - what happens if something goes wrong, access, getting to hospital.

"A number of these waves that we have around the country could be the biggest in the world. There's no doubt about that at all, 100%. It depends on the storms coming across the Atlantic."

Mr Mennie surfed the notorious waves known as Mavericks off California in 2003, Aileen's below the Cliffs of Moher, and was part of a team taking on 90ft waves earlier this year off Portugal.

"I looked for the same characteristics in Ireland as in the US and Hawaii and now we've found waves in Ireland bigger and better. The tables have turned," he said. "We are doing the same as Hawaii but they're in board shorts and sun cream. This is the extreme. We're wearing six millimetre-thick wetsuits in water 10C and near freezing air temperatures."

PA