‘Missing Abroad’ is now leading the search for Lauren Hebden, who began travelling in September 2013. She initially kept in touch regularly via email and Skype. However, this stopped last September – apart from one last email which was sent in December.

The ‘Missing Abroad’ website states that Lauren was last believed to have been on Koh Tao, but does not discount the possibility that she might have moved on to another island.

Koh Tao is renowned as an island paradise – but it has hit the headlines for the wrong reasons in recent months. Two Burmese men are due to stand trial for the murders of British travellers Hannah Witheridge, 23, and David Miller, 24, who were beaten to death on a beach last September. The Thai police investigation has been much criticised, and the accused men have complained that confessions were beaten out of them.

And only last week it emerged that British backpacker Christina Annesley, from Orpington, in south London, had been found dead in her bungalow part way through a four-month journey through south-east Asia.

Investigations are continuing into the death of the 23-year-old former UKIP youth leader, who had been taking antibiotics for a chest infection and is thought to have died as a result of her illness.

Christina was born in New Zealand – in the Wellington city of Lower Hutt – but moved to England with her parents as a baby. Her father, Boyne, told the stuff.co.nz website that he had last heard from his daughter 36 hours before her body was discovered by accommodation staff. “They found her lying in the hut bleeding from the mouth and nose,” he said. 

Mr Annesley said there was no suspicion of foul play or drug abuse. He added that Thai media reports that medicine Christina took for her illness might have been responsible for her death were inaccurate.

Christina’s body is still in Bangkok, and Mr Annesley said the family were becoming angry that it had not been possible to co-ordinate with Thai officials to have his daughter’s body returned to Britain.