British police who travelled to Thailand to review the probe into the murders of Hannah Witheridge, from Great Yarmouth, and David Miller are due to return to the UK, having completed their work "as far as possible".
Officers from the Metropolitan Police flew out last month to work with the Royal Thai Police after an agreement between David Cameron and military ruler General Prayuth Chan-ocha.
It followed international concern about the way the case has been handled by the Thai authorities.
Mr Miller, 24, from Jersey, and 23-year-old Ms Witheridge, from Great Yarmouth in Norfolk, were found dead on a beach on the holiday island of Koh Tao in September.
Two Burmese men, named as 21-year-old bar workers Zaw Lin and Win Zaw Htun, were charged with the killings and paraded in front of cameras after apparently making confessions, but these were later reportedly withdrawn.
UK police concerns are understood to have been around the verification of DNA samples of the suspects and allegations of their mistreatment.
Scotland Yard said officers will compile a report from their review.
Detectives from the United Kingdom who are currently in Thailand reviewing the investigation into the murders of Hannah Witheridge and David Miller have completed their work, as far as possible,
They will now be returning to the UK to compile their report and to update the families of Hannah and David on their findings.
The police team wish to thank the Thai authorities for facilitating the visit.
Thai authorities have banned beach parties on some holiday islands after a Norfolk student and her friend were murdered last month.
23-year-old Hannah Witheridge, from Hemsby near Great Yarmouth, was killed alongside David Miller from Jersey, on the island of Koh Tao.
Two Burmese migrant workers have been charged with the murders. Last week lawyers for the suspects confirmed they had withdrawn their confessions amid allegations they had been tortured by police.
Thai authorities have banned beach parties on some of the country's most popular islands as part of a security clampdown after Jerseyman David Miller and fellow tourist Hannah Witheridge were murdered on the paradise island of Koh Tao.
Authorities say the ban is aimed at tackling crime and negative publicity as the country's tourist season reaches its peak.
Chatpong Chatputhi, Governor of Surat Thani province which includes Koh Tao, said all beach parties would be banned with the exception of the Full Moon Party on Phangan island.
British police are to head to Thailand to help investigate the murder of Norfolk student Hannah Witheridge.Read the full story ›
British detectives travelling to investigate the backpacker murders in Thailand are expected to focus on independent checks of DNA samples central to the case against two Burmese men accused of the crime and their claims to have been mistreated.
Diplomatic sources said Thailand's military ruler accepted the sending of a delegation to investigate the killing of Hannah Witheridge and David Miller when pressed on the issue by David Cameron during their summit meeting.
Obviously it is for the Thai authorities to lead and carry out that judicial process. But it is important that it is fair and transparent and that both of the families can be reassured that it is the murderers that have been brought to justice.
There are two areas we are particularly concerned about. One is the verification of the DNA samples of the suspects, making sure there is further independent verification. And the second is the investigation into allegations of mistreatment of the suspects. What the PM secured this morning was agreement from the Thai PM that we can send some British police investigators to Kho Tao to work with the Royal Thai Police on this.
UK police have been cleared to travel to Thailand to investigate the murders of British tourists Hannah Witheridge and David Miller after the country's military ruler dropped his objections.
The agreement came in a face-to-face discussion between Prime Minister David Cameron and military ruler Gen Prayuth Chan-ocha at a summit - the Asia Europe Meeting - in Italy amid international concern about the way the case has been handled by the Thai authorities.
Miss Witheridge, 23, from Great Yarmouth, and 24-year-old Mr Miller, from Jersey, were brutally murdered on the holiday island of Koh Tao in September.
Thai authorities have charged two bar workers with the murders of the British backpackers amid allegations that the suspects made confessions under duress.
The families of the Burmese workers accused of the murder of two British tourists in Thailand last month have said they are innocent.Read the full story ›
Thailand's Prime Minister is insisting the men accused of killing Norfolk student Hannah Witheridge will be given a fair trial.Read the full story ›
Britain's top envoy in Thailand has met police and Burmese officials amid concerns about the handling of the investigation into the murders of two British backpackers.
Court proceedings have reportedly started against two Burmese men accused of killing David Miller, 24, and 23-year-old Hannah Witheridge from Great Yarmouth on the island of Koh Tao.
According to the Bangkok Post three potential witnesses from Burma will now testify at the court.
Mark Kent, the British ambassador to Thailand, said on Twitter he had taken part in a meeting with Thai police and the Burmese ambassador and on the murders.
Just finished nearly 3 hour meeting with Thai Police, Ministry of Foreign Affairs, Burmese Ambassador and delegation on Koh Tao murders
It comes after a Thai diplomat was summoned to the Foreign Office amid concerns about the police investigation.
Foreign Minister Hugo Swire told Thai charge d'affaires Nadhavathna Krishnamra there was "a real concern" in the UK over the way in which the deaths of Miss Witheridge and Mr Miller have been dealt with.
Thai Police have denied claims the two men suspected of murdering Brits Hannah Witheridge and David Miller have withdrawn their confessions, saying they have "concrete" evidence linking them to the deaths.
The men, who have been named in reports as bar workers Zaw Lin and Win Zaw Htun, are accused of brutally killing Witheridge, 23, and Miller, 24, on the island of Koh Tao in September.
The two suspects, both 21, were charged with three offences - conspiracy to murder, conspiracy to rape and robbery - after local police said the men confessed to the killings.
But reports emerged on Thursday that Aung Myo Thant, a Burmese embassy official, had formally retracted their confessions amid allegations the pair were tortured.
A spokesman for the Royal Thai Police today strongly denied the accusations of torture as he insisted the confessions had not been withdrawn.