A bolt of light flashes across a corridor and the illuminated face of a young boy appears out of the darkness.

This is the mysterious �image which ghost hunter Leonard Low says proves that something paranormal lies beneath the Whittington Hospital in Magdala Avenue, Archway.

The father-of-two, a builder who works in Islington, was visiting a friend in the hospital when he was told by nurses of “a strange presence” in the 19th century arches deep underground.

Armed with his camera and accompanied by a curious Whittington administrator, he descended down to the basement to investigate the paranormal tales.

“Nobody had been in this area for years,” said the 44-year-old. “The ground was crystallised like snow.

“We began walking down this long corridor with files all around us. We walked for around five or six paces when we saw something down the corridor moving.

“There was something hovering in front of us and getting closer and closer.

“We saw this trail of light – it was flashing all over the place.

“Then I saw the ghostly image of the young boy.”

Leonard said he heard �reports from nurses of a ghost-like figure watching them, prompting him to �investigate.

The hospital is steeped in history, dating back to the 15th century when a leper colony was founded there.

Leonard believes the ghostly apparition was the spirit of a child called William who lost his life there in these early years.

It was not the first time the father-of-two has felt what he believes is the presence of those beyond the grave.

When he was 21 an apparition of his sister in her nightgown appeared to him – a fortnight after she died.

And dozens of people have reported ghost sightings at the 18th century tower he owns in Scotland, which was used to imprison and torture women during the bloody witch hunts.

Describing the “extraordinary pain” he experiences when in the presence of a ghost, Leonard said: “I get pins and needles in the back of my head and I find it hard to see.

“It is as if my skin knows there is something there.”

The tale of the Whittington ghost is explored in Leonard’s new book, There Are Such Things.

A spokesman for the hospital said: “Whittington Health is aware that there have been ghost stories about sightings and feelings in the smallpox hospital over the years.

“There is no evidence but the tale continues.”