LONDON • Maybe it was not just the iceberg.

Ever since the Titanic sank more than 104 years ago, killing more than 1,500 people, mystery has swirled around the tragedy. No one doubts the ship collided at high speed with an iceberg off the coast of Newfoundland.

But a new documentary posits that the sinking of the ship - hailed at the time as the largest ever built, and praised for its professed unsinkability - might have been accelerated by a giant coal fire in its hull that appeared to have started as long as three weeks before it set off on its fateful journey to New York from Southampton.

In the documentary broadcast on Britain's Channel 4 on New Year's Day, Irish journalist Senan Molony - who has spent more than 30 years researching the Titanic - contends that a fire in a three-storey-high bunker beside one of the ship's boiler rooms damaged the hull, helping to seal its fate long before it slammed into the iceberg.

"It's a perfect storm of extraordinary factors coming together: fire, ice and criminal negligence," he argues in the documentary Titanic: The New Evidence.

"The fire was known about, but it was played down. She should never have been put to sea."

Mr Molony's potential breakthrough can be traced to an attic in Wiltshire, in south-west England, where a previously unpublished album of photographs chronicling the ship's construction and the preparations for its maiden voyage had been gathering dust for more than a century.

The photographs were discovered by a descendant of a director of Harland and Wolff, the Belfast-based company which built the Titanic. About four years ago, a collaborator of Mr Molony's acquired the rare photographs of the ship, meticulously taken by Harland and Wolff's engineering chief before it left a Belfast shipyard.

When the two men looked closely at the images, Mr Molony said, they were shocked to discover a 30ft-long (9.1m-long) diagonal black mark on the hull's front starboard side, close to where the ship was pierced by the iceberg.

An analysis by engineers at Imperial College London subsequently revealed that the mark was most likely caused by a fire in a coal bunker.

Experts said the theory was compelling but were divided over the role of the fire.

In an interview, Mr Richard de Kerbrech, a marine engineer who has written two books on the Titanic disaster, said the fire would have damaged the ship's bulkhead, a wall of steel within the ship's hull, and made it more vulnerable after it was pierced by an iceberg. An official British inquiry in 1912 mentioned the fire, but the judge who presided over it, whom critics saw as sympathetic to shipping interests, downplayed it.

Mr David Hill, former honorary secretary of the British Titanic Society, has been studying the cause of the sinking since the 1950s. He argued that the damage to the steel walls protecting the hull may have hastened the disaster but the blaze was not the decisive factor.

He said the damage from the iceberg was so great that the vessel would have sunk anyway.

NYTIMES