A review of the technical rules used in container ship design was today recommended after an investigation into the hull failure of a vessel which was grounded off a World Heritage Coast.

The storm damaged 53,000-tonne MSC Napoli - carrying 2,318 containers - was grounded a mile off Sidmouth, east Devon, in January last year amid fears she could break up while being towed to Portland.

Hundreds of people from across the country flocked to nearby Branscombe beach to scavenge everything from BMW motorbikes to disposable nappies when dozens of containers washed ashore.

The bow section of the 275-metre long vessel was towed away for scrap last summer after a series of controlled explosions separated it from the stern, which is in the process of being removed in a months-long operation.

The Southampton-based Marine Accident Investigation Branch investigation report said today the failure to the hull in the region of the Napoli's engine room was due to the vessel's design rather than her material condition or construction.

"The MAIB concluded that this, along with the ship's speed and her loading, caused the vessel to break her back as she headed directly into high seas.

"It has therefore recommended a review of the technical rules used in container ship design.

''As part of the on-going investigation the MAIB identified that container ships of similar design could potentially have the same design flaw and have identified that out of 1,500 vessels screened, 12 require work to bring them up to acceptable safety standards," said the report.

Chief Inspector of the Marine Accidents Investigation Branch, Stephen Meyer, said: "The MAIB has worked closely with the world's leading classification societies to identify any other vessels that may have the same design flaw as the MSC Napoli.

"Out of 1500 vessels screened, 12 required structural work. Until such work can be completed, their safety will be ensured through operational limitations.

"I am very pleased that, at the request of the MAIB, the International Chamber of Shipping and the World Shipping Council have already started work on the development of a Code of Best Practice for the container ship industry.

"This work will take into account the lessons identified by the MAIB investigation and should lead to a much safer industry," he said.

The MAIB has made a series of recommendations to the International Association of Classification Societies to improve the current technical rules regarding container ship design, and to the International Chamber of Shipping and the owners of the vessel Zodiac Maritime Agencies Ltd to make the operation of container ships safer.

The 1991-built Napoli was in the Channel en route from Antwerp to Portugal when the engine room flooded after a hull failure about 45 miles south of Lizard Point, Cornwall.

The MAIB report said after the Napoli hit "several large waves," there was a "large crashing or cracking sound."

Vertical cracks could be seen in the hull below the waterline on the port and starboard sides, and the ship's master assessed that the vessel had "broken her back."

The hull failure was due to "lack of buckling strength in the engine room region," said the MAIB report.

The crew of 26 abandoned ship and were rescued by two Royal Navy helicopters.

The MAIB report said the Napoli was making 11 knots when the hull failed, and a reduction of speed would have "significantly reduced the risk of hull failure."

The Napoli suffered hull damage in dry dock in 2001, and in the same year ran aground at full speed in the Malacca Straits, with repairs requiring 3,000 tonnes of steel.

In December that year, the vessel's hull was damaged berthing in Jeddah and at the same port her hull was scored as she ran aground.