A man who fell asleep during a drug-fuelled sex game has been jailed for two years — after his partner died, tied up, with a gas mask around his face.

Kevin Adams, 54, was found guilty last week of the gross negligence manslaughter of his friend Dohoon Kim, 36, who died when the pair met for casual sex.

Mr Kim wore a gas mask and was tied up by his neck, wrists and ankles during the “extreme” sex session, Bristol Crown Court heard.

The pair had taken mephedrone, known as M-Cat, before engaging in the consensual session at Adams’ home in Exmouth Street, Swindon, Wiltshire, in June 2015.

However, Mr Adams fell asleep — leaving Mr Kim unable to free himself.

Mr Kim died from a combination of the restriction of his airways and the effect of drugs both he and Adams had taken.

Prosecutors said Adams had failed to ensure Mr Kim’s safety during and after sex and then had fallen asleep without removing the gas mask or restraints.

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Adams, who had denied manslaughter, was jailed for two years by Judge Neil Ford QC.

The judge told him: “I have been urged to pass a sentence that falls within the sentences that could be suspended.

“I regret to say I cannot agree with this submission. Even though this death can be regarded as a tragic accident it nonetheless was caused by your gross negligence and I cannot lose sight of the fact a life was lost.”