The Independent Police Complaints Commission (IPCC) said four senior officers, including Deputy Assistant Commissioner Cressida Dick, should not face disciplinary action over the shooting of Brazilian Jean Charles de Menezes.

But the 27-year-old electrician's family branded the decision - which brings a series of police watchdog reviews into the tragedy to a close - a "scandal".

Campaigners criticised the IPCC's decision to conclude the case before an inquest - expected to take place next year - and accused the watchdog of trying to bury bad news. But Scotland Yard said the decision was a "move forward" which would finally end uncertainty hanging over the four officers and their families.

Eleven other Metropolitan Police officers originally questioned under caution over the killing had already been told they would not face disciplinary action. That left Ms Dick and three other senior officers - known only by the codenames Silver, Trojan 84 and Trojan 80 - still facing possible action.

No individual faced criminal charges but the force itself was convicted on a general health and safety count at the Old Bailey last month.

Mr Menezes was gunned down at close range in a Tube carriage at Stockwell station in south London on July 22 2005. Police had mistaken him for failed suicide bomber Hussain Osman, part of the gang which tried and failed to blow up passengers on Tube trains across the capital the previous day.

The Metropolitan Police was eventually fined £175,000 and ordered to pay £385,000 costs after being convicted of exposing the public to risk at the Old Bailey trial. But the jury took the unusual step of adding a rider to its verdict saying that "no personal culpability" should be attached to the Deputy Assistant Commissioner.

They concluded that Ms Dick, who was the gold commander in charge of the operation that day, had been fed "inaccurate information". That proved crucial in determining the IPCC decision. The commission became convinced that no disciplinary panel would be likely to come to a different conclusion from that of the jurors who sat through weeks of evidence.

"The IPCC cannot foresee any circumstances in which new evidence might emerge which would cause any disciplinary tribunal to disregard the jury's rider," the commission said in a statement announcing the decision.