A British banker has been found guilty of murdering two Indonesian women after promising to pay them for sex in his upmarket Hong Kong apartment.

Rurik Jutting denied the two charges on grounds of diminished responsibility but was convicted by a jury in Hong Kong on Tuesday.

The 10-day trial heard, in gruesome detail, how the 31-year-old Cambridge graduate slashed the throats of Sumarti Ningsih, 23, and Seneng Mujiasih, 26.

The former securities trader was accused of holding Ms Ningsih captive for three days before beheading her and stuffing her dead body in a suitcase. He stored it on his 31st-floor balcony close to the notorious Wan Chai red-light district until calling police.

The jury, who had to sit through his own smartphone footage of the former Bank of America Merrill Lynch employee torturing Ms Ningsih, took around four hours to find the expressionless Jutting guilty.

The two victims' families released statements calling for severe punishment as well as compensation over the women's deaths because they were the main breadwinners.

The family of Ms Mujiasih, a bar worker and former maid, said they were “devastated” and hoped Jutting could be executed “if possible”, the BBC reported.

The family have also reportedly called on the Indonesian government to provide a scholarship for her seven-year-old son.

In a letter read out to the court by defence counsel Tim Owen after the verdicts, Jutting said: “My actions regarding the deaths of Ningsih and Mujiasih – my actions preceding their deaths – were horrific even by the standard of homicide trials.”

Seneng Mujiasih, also known as Jesse Lorena, was found dead in Rurik Jutting's luxury flat (Rex)

Jutting said he was “haunted” by what he had done and was “aware of the acute pain I've caused to their loved ones”.

“The evil that I've inflicted cannot be remedied by me,” the letter said.

“I'm sorry, I'm sorry beyond words.”

The former history and law student, who lived in a flat boasting a rooftop pool after moving to Hong Kong in 2013, debated for his college Peterhouse and was secretary of the history society.

He has been described by friends as bright but aloof and “socially awkward”.

An Indonesian migrant worker at a vigil for Seneng Mujiasih and Sumarti Ningsih in Hong Kong's Victoria Park on the eve of Rurik Jutting's trial (AFP/Getty)

The graphic trial painted a picture of a friendless loner living off takeaway food, drinking, binging on cocaine and amassing huge debts.

He told police interviewers: “She was unlucky to be the person in my flat when I realised that physically hurting someone under cocaine was something I gained satisfaction from.

“It awoke a part of me that I never knew existed.”

Jutting, who was taking cocaine in the run-up to the murders, said he spent more than £820,000 on the drug over two years and consumed as much as 10g and four bottles of wine in one day.

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His defence counsel referred to this, and an alleged sexual assault he was subjected to as a 16-year-old at Winchester College, in an attempt to explain his actions.

Forensic psychiatrist Richard Latham said Rurik Jutting suffered from narcissistic personality disorder and sexual sadism disorder.