Murderers of British backpackers to be executed after losing last-ditch appeal in Thai court

David Miller and Hannah Witheridge were killed while they were travelling in Thailand. Photo / Facebook

Two men found guilty of murdering a pair of British backpackers in Thailand will be executed after their last-ditch appeals were thrown out.

Hannah Witheridge and David Miller's bodies were found on tourist islands Koh Tao on September 2014.

The tourist hotspot has been nicknamed "death island" following a string of tourist deaths while holidaying there.

Witheridge, 23, had been raped and bludgeoned to death while Miller, 24, suffered shocking head injuries, according to police.

Witheridge and Miller met on Koh Tao while staying at the same hotel in Thailand.

The pair were killed with a wooden hoe as they walked back to their hotel rooms in the dark of the night.

Burmese migrant workers Zaw Lin and Wai Phyo were found guilty of the murders in 2015 and sentenced to death.

Zaw Lin (R) and Wai Phyo (L) will be executed after a last-ditch appeal failed. Photo / Getty

Supporters of the two migrant workers claim the pair had been framed and alleged the courts had mishandled the evidence.

However, Lin and Phyo had initially confessed to the murders before retracting their statements, claiming they were tortured when being questioned.

Despite an appeal, the three judges who handed down the original guilty verdicts and death penalties say the forensic evidence met "international standards".

The trial was also plagued by accusations of human rights abuses and in 2016 international legal and forensic scientists said a DNA investigation by Thai Police Forensics Laboratory was incompetent with no evidence.

The pair were also asked to reconstruct the attack on Sairee Beach, accompanied by police.

Bizarre pictures show the pair handcuffed, wearing bicycle helmets during the reconstruction.

Bizarre pictures showed the two killers in helmets after they re-enacted the crime with police. Photo / Twitter

The legal team defending the two men also said the evidence collected by police was unreliable and not in accordance with internationally accepted standards.

"The death penalty sentence against the two accused and their conviction should be reversed and quashed," Andy Hall, an adviser to the two men's legal team, said ahead of their appeal.

"DNA and forensics evidence relied on to convict Zaw Law and Wai Phyo, and sentence them to death in the Koh Tao murder case was fundamentally flawed and unreliable in terms of international standards."