The seat of the fire that caused major damage to the Cutty Sark is being treated as a crime scene, police told the ship’s trustees yesterday.

Forensic scientists and fire investigators have cordoned off the area around the rear deck hatch. Their first tasks are to determine what ignited the blaze and whether it was an accident or act of arson.

The investigation began in earnest as the Duke of Edinburgh, president of the Cutty Sark Trust, visited the ship and an anonymous donor pledged £100,000 to help to save her.

The Duke walked around the stricken tea clipper, peering closely at the shell of iron and burnt timber. He compared the damage to that of the fire at Windsor Castle in 1992. Earlier he and the Queen visited the National Maritime Museum to celebrate the completion of the Time and Space extension at the Royal Observatory.

Detectives were viewing CCTV footage from cameras around the site at Greenwich, southeast London. Officers said that the film showed a number of people in the area before the fire broke out at 4.46am and a silver car leaving the area. They are anxious to trace those people and the vehicle.

One nightwatchman was on duty but none of the team involved in the £25 million project to restore the famous ship had been there since Friday afternoon.

The tea clipper has been a tourist attraction in her dry dock in Greenwich for 50 years. Many of her original features – including the masts and master’s cabin – had been removed for the renovations but the vessel still suffered severe damage. The decks were destroyed, the unique iron hull that made her one of the fastest sailing ships has been distorted by heat and there is concern about the vessel’s stability. Heavy timbers have been removed to prevent them falling and causing further damage.

A spokeswoman for the Metropolitan Police said that investigators had to work cautiously inside the damaged frame of the ship. The London Fire Brigade said that it could be a number of days before the investigation produced firm conclusions.

Richard Doughty, chief executive of the Cutty Sark Trust, told The Times: “Forensic scientists have been on board since morning and the site remains a crime scene – that is the phrase that has been used to me. The area around the aft hatch, which has stairs for public access, is cordoned off and that seems to be the principal focus of their attention.”

Mr Doughty said that the trustees were having to reevaluate the scale and nature of the restoration project, which envisaged suspending the ship above the dry dock to relieve pressure on the keel and show off her revolutionary design. The project already had a funding shortfall of £7 million and the fire is estimated to have added at least £5 million to that.

Mr Doughty said: “We have a different project on our hands now. We are having to lay off some of the designers who were working on the restoration, at least temporarily, while we put our recovery plan in place.”

An appeal for help in restoring the ship raised more than £120,000 within 36 hours of the fire. The gift of £100,000 was made by a telephone donor who requested anonymity.

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