THAI police launched an investigation into the brutal drug rape of a British backpacker on notorious “Death Island” yesterday - two months to the day after it was reported.

The 19-year-old tripper was subjected to a vicious sexual assault on a paradise beach and robbed after her drink was spiked in a bar on Koh Tao.

She fled the island in terror the next day fearing reprisals if she went directly to local police and reported her ordeal when she reached neighbouring Koh Phangan.

But the victim claims police there insisted they could only note details of the robbery and refused to pass on the rape allegations to police on Koh Tao.

Koh Tao Police later insisted they knew nothing of the rape - on June 26 at the beauty spot where Britons Hannah Witheridge and David Miller were battered to death in 2014.

Police on the crime-plagued isle u-turned last week after the girl’s family them of mounting a shameful cover-up.

But vital CCTV and forensic evidence looks certain to have been lost owing to the two month delay.

Authorities finally confirmed they had set up a committee to investigate the rape yesterday - while bemoaning the lack of evidence.

But a black t-shirt worn by the pretty British teenager could boost the probe after traces of foreign DNA, believed to be from the rapist, was found on it.

The victim sealed it in a plastic bag and handed it to police in the UK because she did not trust Thai officers - and it may now be tested in the UK to help identity the attacker.

Police Colonel Krissana Pattanacharoen said the independent committee will also try to establish why rape claims were not probed sooner.

The victim returned to the UK on July 2 and is understood to have gone with her mother to report the rape formally at London’s Lewisham Police Station. She has also checked into a rape crisis centre in the capital.

Police commander Major General Apichart Boonsrirote Surat Thani flew by helicopter to Koh Tao with other senior cops from the Thai mainland to launch the probe yesterday. (Mon)

He said: ''We currently have no evidence of the actual rape only the movement of the girl and her friend.

''Police have arrived on the island today to find evidence. We will look at the place where she said she was raped.

''Officers will check CCTV cameras from the area. A lot of the footage from the date has already been overwritten.

''A committee will now be set up to establish the facts.”

Island authorities are believed to be desperate to cover up the recent catalogue of shocking crimes fearing their tourist trade will be decimated.

Hannah Witheridge, 23, from Hemsby, Norfolk, and David Miller, 24, from Jersey, were found beaten to death on Sairee Beach on September 15, 2014.

Post-mortem examinations showed that the young backpackers, who had met on the island, both suffered head wounds and that Hannah had been raped.

Two Burmese migrant workers Zaw Lin and Wai Phyo were sentenced to death for the killings and are currently on Death Row awaiting the result of an appeal.

Other Brits found dead on the island included Ben Harrington, 32, from Reigate, Surrey who died in 2012.

Thai police said he died after his motorbike crashed into an electricity pylon, but his mother Pat believes he may have been killed by robbers who took his watch and wallet.

The body of British bricklayer Luke Miller, 24, from Newport, was found at the bottom of a hotel swimming pool at Sunset Bar on Sairee Beach in 2015.

British holiday-maker, Nick Pearson, 25, from Derby, was also found drowned but his parents suspected foul play after a post mortem examination revealed a head wound.

A Foreign Office spokeswoman said: “Our staff are assisting a British woman in Thailand, and are in contact with her family and the Thai authorities.”