The jury hearing the inquest of Jean Charles de Menezes were barred from finding that he was illegally killed by the Metropolitan Police, in a surprise order that prompted members of his family to walk out of court.

Sir Michael Wright, QC, ruled yesterday that jurors would not be allowed to consider a verdict of unlawful killing. In the closing stages of the 11-week inquest, which has involved 100 witnesses and is estimated to have cost £3 million, Sir Michael said that the evidence did not justify such a conclusion.

Mr de Menezes, 27, an electrician, was shot seven times in the head by armed police who mistook him for a suicide bomber on a London Underground train in July 2005.

The coroner said that no individual – not the firearms officers who shot Mr de Menezes, nor their Scotland Yard commanders – could be held liable in criminal or civil law for his death.

Sir Michael, a retired High Court judge, told the eleven jurors that they could only consider two outcomes: either that Mr de Menezes was lawfully killed or an open verdict.

Referring to Mr de Menezes’s mother, Maria Otone de Menezes, who sat through most of the inquest, he said: “I know that your heart will go out to her. But these are emotional reactions, ladies and gentlemen, and you are charged with returning a verdict based on evidence. Put aside any emotions – put them to one side.”

The inquest, held in the John Major Room at the Oval cricket ground in South London, has heard conflicting and controversial evidence.

Jurors were told that police surveillance officers, given the task of finding one of the four bombers who tried to detonate suicide devices in London on July 21 2005, were sent out the following morning without a picture of the man they were looking for. Although Mr de Menezes was never positively identified as the terrorist suspect, specialist firearms officers ran on to a Tube train at Stockwell and shot him dead.

One of the armed officers, “Charlie 12”, claimed that he had shouted “armed police” and opened fire only after Mr de Menezes had stood up and advanced towards him. None of the passengers on the carriage recalled hearing a warning shouted or seeing Mr de Menezes stand up before he was held down in his seat and shot. One woman said that she thought that the police officers were “out of control”.

Deputy Assistant Commissioner Cressida Dick, the Gold Commander on the operation, said in her evidence that no officer had done anything wrong or unreasonable.

Sir Michael said that his decision to disallow an unlawful killing verdict was a reflection that the evidence did not point to any individual being responsible for the death. He said: “All interested persons agree that a verdict of unlawful killing could only be left to you if you could be sure that a specific officer had committed a very serious crime – murder or manslaughter.”

Sir Michael warned jurors that they must not attach criminal or civil fault to any individuals. But the jury were not barred from concluding that the police had made mistakes. He added: “In directing you that you cannot return a verdict of unlawful killing, I am not saying that nothing went wrong on a police operation which resulted in the killing of an innocent man.”

Last year, an Old Bailey jury found the Met guilty of breaches of health and safety law in the operation. The force was fined £175,000.

Sir Michael said that he wanted the jury to consider whether the officer had shouted a warning before opening fire, whether there had been communication failures between Scotland Yard and officers on the ground and why Mr de Menezes was not stopped before boarding public transport.

The coroner continues his summing-up today.

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