Hero British diver who saved Thai boys from flooded cave says he feared the worst as he reveals mission was 'most dangerous thing I've ever done'

Rescuers involved in the rescue of 12 Thai boys and their football coach from a flooded cave have opened up about the dangerous mission.

The footballers were freed from Tham Luang cave in northern Thailand following a complex operation involving an international team of diving experts and military professionals.

British cave diver Jason Mallinson told ABC TV's Four Corners: "It's one of the most difficult and dangerous and risky things I've ever done."

The 50-year-old, who was tasked with guiding the children through the murky waters and flooded passageways, added that the operation was risky "in terms of the people I was responsible for".

Meanwhile US Mission Commander Major Charles Hodges said he expected "three, four, possibly five" of the boys would die during the rescue operation.

Each of the boys, aged 11 to 16 and with no diving experience, was guided out by a pair of divers during the three day mission.

The route, in some places just a crawl space, had oxygen canisters positioned at regular intervals to refresh each team's air supply.

Experts had warned at one point that it may be too risky to dive the youngsters out.

Mr Mallinson was among the experts divers reponsible for bringing the boys through the most complicated spots.

Speaking of the daring mission, Mr Mallinson said he "wasn't 100 per cent confident" of getting the boys out of the cave alive.

The hero diver was tasked with taking the boys from Chamber nine the whole way out of the cave.

He said: "I was confident of getting the kid out, I wasn't 100 per cent confident of getting him out alive.

"Because if we bashed him against a rock too hard and it dislodged that mask and flooded his mask, he was a goner."

He described the process as “mentally exhausting”, especially on the last day when there was no visibility.

“I had to have the lad really close to me because if you didn’t, you were bashing his head against the rocks,” he said.

The diver held his head above the boy's so that his head hit the rocks instead.

“The visibility was that bad, you couldn’t see the rock until you actually hit it,” he said.

The Wild Boars football team are still recovering in hospital following the rescue.

On Sunday, Thai officials released a picture of all 12 of the boys and their football coach posing with a sketch of ex-Navy Seal diver Saman Kunan, who died while trying to rescue them.