Footage shows divers searching through the sunken wreckage of a boat that caught fire and trapped a British tourist who is believed to have perished onboard.

Backpacker Alexandra Clarke, 26, from Lambeth, South London, was reportedly using the toilet when a blaze erupted from an air compressor on the wooden vessel five miles from 'Death Island' 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 based on the island.

They were all rescued by passing boats before the vessel sank, with Alexandra feared to have been trapped in the toilet next to the flames and explosions.

Police said today, Tuesday, that Alexandra remained missing. Boats, specialist divers and helicopters are now scouring the area where the ship sank.

They are holding out hope that Alexandra was picked up by a passing ship and taken ashore but are also searching for her body amid fears she was burned alive as the ship went down or jumped overboard and drowned.

Naval Captain Natthapol Sinphulphon, Deputy Director of the Surat Thani Marine Police Division, said: 'Divers were unable to find the body of the missing tourist in the sunken ship. She is still missing.

'It is possible that she is trapped inside the wreckage. The next step will be to lift the ship to the surface for it to be inspected.'

The tourists were on the boat for a scuba diving trip in the idyllic waters around Koh Tao. They were around five to six nautical miles from the island when a fire started.

Police said that a Burmese crew member, Teo, 48, was operating an air compressor to fill diving tanks when a malfunction occurred, causing the compressor to catch fire.

The flames started close to the engine room next to the toilet at the back of the boat, leaving anyone inside the lavatory trapped by the flames.

Investigators believe that compressed air in the scuba diving tanks filled to 3,000psi, as well as fuel onboard, caused the fire to spread rapidly.

Police said the wooden boat, named Davy Jones Locker, was owned by the Davy Jones Locker Diving Company from Koh Tao in Surat Thani province. Captain Tawee Petchburipakdee, 66, was operating the vessel at the time.

Naval Captain Natthapol added: 'On that day, there were about three to four tour boats passing through that area. They stopped to assist the tourists immediately before coordinating with authorities for additional help.

'However, the other boats were hesitant to approach the incident site due to the fear of exploding tanks.

'When the dive team entered the boat to search, they could not locate the missing tourist, and the boat sank shortly after. It was also getting dark, and by 8 PM, the dive team was exhausted, so they contacted the Maritime Enforcement Coordination Center (MEC) for assistance. The area where the boat sank is up to 45 metres deep, requiring special dive skills from the MEC.'

Police Colonel Sarayut Burivachira, the Superintendent of Koh Tao Police Station, said the owners of the boat and the crew were being investigated.

He added: 'Investigators have filed charges of negligence against the boat operator and the staff responsible for controlling the oxygen filling, which led to the fire and property damage.

'Meanwhile, the Koh Phangan Marine Office is proceeding with legal actions under the Thai Shipping Act of 2003 and its amendments. They have issued a warning for safe navigation and ordered the boat owner to salvage the wreck within 15 days of receiving this notice. The boat is prohibited from further use until it is repaired and deemed suitable for operation.'

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.'

The Davy Jones Locker diving centre was asked in writing - and read the message - about the case but did not respond to a request for comment.