A British tourist is missing feared dead after a fire ripped through a diving boat off the coast of Thailand's notorious 'Death Island'.

Backpacker Alexandra Clarke, 26, from Lambeth, South London, was reportedly using the toilet and trapped when a blaze erupted from the engine of the wooden vessel near Koh Tao on Sunday morning.

Officials said at least 16 tourists were onboard the boat, named Davy Jones Locker, as well as two crew and four instructors from the scuba diving firm.

They are understood to have been rescued by passing boats but Alexandra was still unaccounted for on Sunday afternoon.

Police said she remained missing, amid fears she had been engulfed in the flames as they rapidly spread or knocked out by explosions.

Compressed air in the tanks filled to 3,000psi as well as fuel onboard are understood to have caused the fire to have spread. The toilet is often located at the back of the boat on the bottom deck next to the engine.

Footage shows how the inferno ravaged the large wooden cabin at the rear of the boat as shocked holidaymakers on passing boats looked on.

Captain Natthaphon Sinpoonphon, Deputy Director of the Thai Maritime Enforcement Command Center of Surat Thani, said the blaze started at around 9 am local time. An emergency call was received shortly after.

He said: 'The boat was carrying a group of tourists for a diving excursion from Koh Tao. It was between five and six nautical miles away from the island.

'A fire started in the engine room and spread through the boat rapidly.

'Thai-MECC Surat Thani coordinated with private vessels and volunteers to safely evacuate the tourists and crew members onto another boat.

'Meanwhile, another team of volunteers worked to control the fire. Preliminary reports indicate that the engine room, captain's cabin, and rear restroom were damaged. The exact cause of the fire remains under investigation.'

Lieutenant Colonel Nattapol Sinpunphol, deputy director of the Surat Thani Marine Department, said rescue teams were initially unable to get close to the boat because of the flames. There were also fears of further explosions from the tanks and fuel onboard.

He added: 'The search is continuing for one missing tourist, a female, Alexandra Clarke, from the United Kingdom.

'The conditions at sea are dangerous with the wind and currents. All boats in the area have been notified. Search and rescue teams were immediately mobilised.'

Koh Tao is one of the world's most popular scuba diving locations but it has been dubbed 'Death Island' due to the alarming number of young tourists who have died in mysterious circumstances. Dozens have been killed - though the actual number could be much higher, with many deaths covered up to protect the lucrative tourism industry.

The most high-profile case was the death of Hannah Witheridge and David Miller, who were bludgeoned to death on Sairee Beach in in September 2014.

Two Burmese labourers were allegedly framed for the murders in order to protect the real killer - the son of a prominent local family - and wrap the case up quickly amid unwanted international scrutiny.

Prominent Australian lawyer Ian Yarwood, who has campaigned for the two Burmese boys to be released, has made repeated calls for tourists to avoid the island due to 'crime, corruption and poor health and safety'.

He added: 'My heart goes out to the family and friends of Alexandra Clarke. I suspect the fire on her dive boat was probably avoidable or could have been suppressed with proper safety equipment and training.

'Tragically, safety standards around Koh Tao are appalling compared with those in the West. Fires on Koh Tao boats and ferries are far too common.

'The fire on the Koh Tao ferry on 4 April 2024 claimed the lives of two Myanmar workers. There were only 50 life jackets for the 108 passengers and crew on board.

'Sunday's tragedy occurred just two months after Canadian backpacker, Ashlie Toews, 22 was struck from behind and killed by a truck while she and her boyfriend sat on a stationary scooter at the bottom of a hill on the island.'