The family of Jean Charles de Menezes have lost a human rights challenge over the decision not to charge any individual police officer following his death.
A case brought by relatives of the Brazilian, who was mistaken for a suicide bomber and shot dead by police marksmen more than a decade ago, was rejected by European judges.
Lawyers for the family argued an assessment used by prosecutors is incompatible with Article 2 of the European Convention on Human Rights, which covers the right to life.
However, the European Court of Human Rights' Grand Chamber found there had been no violation.
Mr de Menezes's cousin Patricia da Silva Armani said the family are "deeply disappointed".
She said: "We had hoped that the ruling would give a glimmer of hope, not only to us, but to all other families who have been denied the right to justice after deaths at the hands of the police.
"We find it unbelievable that our innocent cousin could be shot seven times in the head by the Metropolitan Police when he had done nothing wrong and yet the police have not had to account for their actions.
"As we have always maintained, we feel that decisions about guilt and innocence should be made by juries, not by faceless bureaucrats and we are deeply saddened that we have been denied that opportunity yet again."
Lawyers for the family claimed the evidential test applied by the Crown Prosecution Service - that there should be sufficient evidence for a "realistic prospect" of conviction - is too high a threshold.
It means that, in effect, the decision not to bring a prosecution was based on a conclusion that there was less than a 50% chance of conviction, they argued.
The Strasbourg court said: "The frustration of Mr de Menezes's family at the absence of any individual prosecutions is understandable."
However, its judgment concluded that "it cannot be said that the domestic authorities have failed to discharge the procedural obligation under Article 2 of the Convention to conduct an effective investigation into the shooting of Mr de Menezes which was capable of leading to the establishment of the facts, a determination of whether the force used was or was not justified in the circumstances and of identifying and - if appropriate - punishing those responsible".
Article 2 did not require the test to be lowered in cases where deaths occurred at the hands of state agents and all aspects of the authorities' responsibility for the shooting had been thoroughly investigated, the court found.
The decision not to prosecute any individual officer was not due to any failings in the investigation "or the State's tolerance of or collusion in unlawful acts", the judgment said.
It added: "Rather, it was due to the fact that, following a thorough investigation, a prosecutor considered all the facts of the case and concluded that there was insufficient evidence against any individual officer to meet the threshold evidential test in respect of any criminal offence."
The complaint also challenged the domestic definition of self-defence but the court found the test applied was not significantly different from its own standard.
Mr de Menezes, 27, was shot by firearms officers at Stockwell Underground station in south London on July 22 2005, a fortnight after the July 7 bombings.
The following year the CPS announced that no individual should be charged in connection with Mr de Menezes's death.
In 2007 the Met was fined £175,000 after being convicted of breaching health and safety laws.
An inquest jury later rejected the police account of the shooting and returned an open verdict. The coroner had ruled out a verdict of unlawful killing.
In 2009, the electrician's family agreed an undisclosed settlement with Scotland Yard.
Following the judgment on Wednesday, de Menezes family solicitor Harriet Wistrich said it was a "very disappointing decision" but noted that four of the 17 judges dissented.
A government spokesman said it "considers the Strasbourg court has handed down the right judgment", adding: "The facts of this case are tragic, but the Government considers that the court has upheld the important principle that individuals are only prosecuted where there is a realistic prospect of conviction."