It was a 12-hour ordeal that resulted in four civilian rescuers going missing after their boat hit a downed power line in rushing floodwaters caused by Tropical Storm Harvey, while their friend, together with a British photographer and his American colleague who had gone to cover a story, survived by clinging to a tree all night.

London-born freelance photographer Ruaridh Connellan, 26, who now lives in Brooklyn and was brought to a Houston hospital by police on Tuesday morning, recounted the story of his incredible ordeal.

Together with a colleague, on Monday afternoon Mr Connellan had found a group of five men preparing to launch their boat into floodwaters that had stranded one of the men's grandmothers in her house.

“We got in the boat with them and began heading towards her house to rescue her,” Mr Connellan told the Telegraph. “We thought it would be a good story; good pics.”

But he said as soon as the boat entered the water it veered out of control and immediately started heading towards some low-hanging power lines.

“Everyone jumped ship but we got zapped. I was in the water right by these power lines and I just felt this electric current go through my body and I thought I was done for. Then it stopped but it started again. I could see four of the men lying in the water – one of them, floating on his back in his lifejacket."