The coroner at the inquests into the deaths of 21 people in the Birmingham pub bombings has instructed the jury to return a verdict of unlawful killing.
Sir Peter Thornton QC has begun summing up at the end of six weeks of evidence about explosions at two city centre pubs on 21 November 1974.
He directed the jury to answer "Yes" to the question whether the 21 people were unlawfully killed.
"This was murder in ordinary language and murder in law," he said.
The bombs killed 21 and injured 220 at the Mulberry Bush in the base of the city's Rotunda and the Tavern in the Town in nearby New Street.
The coroner listed eight questions about the bombings which the jury had to answer, including the adequacy of warnings telephoned to a local newspaper, whether the authorities had forewarnings of the attacks and whether the IRA was responsible.
He added: "Consider the nature of the planting and priming of the bombs, the location of the bombs in crowded pubs. When you take this all into account there is only one answer.
"This was murder and you can be sure of it."
The jury was also advised to "set aside their feelings" in reaching their verdicts.
"You have heard a great deal of moving and distressing evidence which as fellow human beings we are touched by," Sir Peter said.
"Whatever your feelings you must put them to one side. Come to your decisions coolly and calmly on the evidence."
The inquests have heard from a convicted IRA bomber known as "Witness O" who said four men - Seamus McLoughlin, Mick Murray, Michael Hayes and James Gavin - were responsible for planting the bombs.
But the coroner said it was not for the jury to name the alleged bombers, adding: "It is not your task to decide who carried out the bombings."
He said that was a matter for the police, the Crown Prosecution Service and the courts.
Six men were jailed in 1975 for the bombings, but their convictions were quashed by the Court of Appeal in 1991.
The jury is expected to retire on Thursday to consider its verdicts.
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