A search has resumed in Thailand for a 26-year-old woman from south London who is missing after a boat carrying tourists caught fire and sank off the coast of the island of Koh Tao during a diving trip.

Alexandra Clarke was aboard the vessel when the fire broke out on Sunday morning, the Surat Thani Provincial Public Relations Office said.

On Monday, divers searched the wreckage of the boat and the surrounding area but found no trace of Ms Clarke, from Lambeth, who is believed to have been in the toilet when the fire started.

The Foreign and Commonwealth Office said it was “supporting the family of a British woman who is missing in Thailand and are in contact with local authorities”.

Koh Tao Police said it believed the boat’s fuel tank overflowed when it was refilled during the journey. Officers have charged the captain and crew with negligence.

The vessel left shore at about 07:30 ITC (00:30 GMT) to carry the group to a popular diving spot, the Southwest Pinnacle, local police said.

Col Sarayuth Buriwachira from Koh Tao Police said the fire broke out at about 10:00 ITC after a crew member put too much fuel in the engine.

“When he started the engine, a spark occurred, causing the engine to catch fire and spread, causing the entire ship to burn and eventually sink into the sea,” Col Buriwachira said.

The fire spread quickly, engulfing the engine room and forcing the divers, instructors and crew to jump into the sea, he added.

According to the provincial office’s Facebook page, authorities worked with private boat operators and volunteers to help evacuate tourists and crew to another boat safely, but that Ms Clarke was not among them.

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