The search for the body of a British yachtsman allegedly bludgeoned to death by pirates is continuing off Thailand.

An earlier report that the body of Malcolm Robertson, 64, from, St Leonards, East Sussex had been retrieved from the sea has been discounted by the Foreign and Commonwealth Office.

It is thought that he was beaten with a hammer and had his throat cut by men who boarded his boat on Monday, before his body was thrown into the Andaman Sea.

The Foreign Office said: ‘The Thai authorities are continuing their investigation and are still searching the area.’

Thai police arrested and charged three fishermen from neighbouring Burma with murder and robbery on Tuesday. They allegedly confessed to climbing aboard the yacht, beating Mr Robertson with a hammer and throwing his body overboard after he found them trying to steal a dinghy.

They then forced Mr Robertson’s 57-year-old wife Linda to steer the yacht to shore after she was stripped naked and tied up for hours, police said. The men fled in a raft when they saw Thai national park employees passing by in a boat, it was claimed.

The pirates will not be prosecuted for murder if Mr Robertson’s body is not found, Thai authorities have said. Without a body, no such charge can be brought under Thai law, even though the three Burmese men, have confessed to the death, and the boat was covered in blood.

Mrs Robertson spent nearly 10 hours testifying before two courts on Friday, recounting in detail how she heard her husband being attacked before treading in his blood on the deck of the boat as she tried to escape her captors.

She said that she was in a ‘state of total disbelief’ at the decision not to charge his killers for the murder.

The retired couple had been sailing their Bruce Roberts 44ft cutter, Mr Bean, from Phuket to the Malaysian island of Langkawi.