A coroner investigating the holdall death mystery of MI6 spy Gareth Williams has ruled out an unlawful killing verdict.

Dr Fiona Wilcox will deliver a narrative conclusion at lunchtime after reflecting on seven days of inquest evidence.

Relatives' barrister Anthony O'Toole said: "We would invite you to say that, on the balance of probability, there was an unlawful killing in this case."

Hearing legal submissions, Dr Wilcox said open and narrative verdicts were the only options available to her. But she added: "An open verdict would not do justice to the positive findings I can make."

Members of the high-flying codebreaker's family are expected to arrive at Westminster Coroner's Court before Dr Wilcox delivers her decision.

A 21-month inquiry to find out how Mr Williams ended up locked inside a bag in his bathroom has so far drawn a blank.

Dr Wilcox angrily attacked police and MI6 on Tuesday for evidence disclosure failures surrounding belongings left at Mr Williams's desk. Nine computer memory sticks and a black bag were overlooked in the inquiry until the lead detective, Jackie Sebire, was made aware this week.

Ms Sebire said Scotland Yard will review lines of inquiry in its investigation in the wake of the inquest.

Mr Williams, a 31-year-old fitness enthusiast originally from Anglesey, North Wales, was found naked, curled up in a padlocked holdall in the bath of his flat in Pimlico, central London, on August 23 2010.

Pathologists said he would have suffocated within three minutes if he was alive when he got inside the 32in (81cm) by 19in (48cm) red North Face bag. Poisoning and asphyxiation are the "foremost contenders" in solving the death riddle, they said.