Image copyright Family photos Image caption Hannah Witheridge and David Miller were found close to bungalows where they had been staying

The Thai charge d'affaires has been summoned to the UK Foreign Office over concerns about the inquiry into the murders of two British tourists.

Hannah Witheridge, 23, and 24-year-old David Miller were killed in an attack on the island of Koh Tao last month.

Foreign Office minister Hugo Swire told the diplomat there was "concern" about how the investigation had been handled.

Two Burmese workers are said to have confessed to killing the pair, who were discovered on a beach on 15 September.

Police in Thailand have denied subsequent reports that the two men had withdrawn their confessions.

Post-mortem examinations found Mr Miller, from Jersey, died from drowning and a blow to the head, while Miss Witheridge, from Great Yarmouth, died from head wounds.

'Fair and transparent'

The Foreign and Commonwealth Office (FCO) said the summons of Nadhavathna Krishnamra on Monday followed a call made by Mr Swire to Thailand's deputy prime minister and foreign minister earlier this month.

In a statement, the FCO said: "Mr Swire stressed that there was a real concern in the UK about how the investigation has been handled by the Thai authorities.

"He said that it was crucial for the investigation to be conducted in a fair and transparent way."

Image copyright Reuters Image caption The island of Koh Tao is a popular destination for tourists

The FCO added: "Mr Swire emphasised how important it was that the UK and Hannah and David's families received regular updates on the investigation's progress.

"He also noted his concern about the way that the police had engaged with the media on the case and reiterated that the UK police stood ready to assist with the investigation and subsequent legal process."

The men charged with the killings were paraded in front of cameras at a news conference after apparently making confessions,

The FCO previously said it was "concerned" about reports the Burmese workers have been mistreated by Thai police and had raised those concerns with the relevant authorities.

The two suspects, both aged 21, are charged with conspiracy to murder, conspiracy to rape and robbery.

Funeral services for Mr Miller and Ms Witheridge have taken place in recent weeks.

Koh Tao