An officer who killed a man during a foiled attempt to free two prisoners can face misconduct proceedings, the Court of Appeal has ruled.
Jermaine Baker, 28, was shot dead by a firearms officer near Wood Green Crown Court in north London in 2015.
The police watchdog had directed the Met Police to bring disciplinary action against the officer but that was quashed by the High Court last year.
But appeal judges overturned the ruling saying proceedings were "justified".
In December 2015, Mr Baker was in a stolen Audi with two other men, waiting for Izzet Eren and a co-defendant to arrive in a security van from Wormwood Scrubs prison to be sentenced for a firearms offence.
While monitoring the three men via two bugging devices, police moved in on the vehicle and Mr Baker was fatally shot by a firearms officer referred to as W80.
The Independent Office for Police Conduct (IOPC) had said the force should bring disciplinary proceedings for gross misconduct against W80 following an investigation.
However, the officer successfully challenged the decision in the High Court in August last year.
The IOPC took the ruling to the Court of Appeal where judges said their decision to direct the Met to bring misconduct proceedings against W80 still stands.
In a summary of the ruling, judge Sir Geoffrey Vos said: "The IOPC was justified in concluding that it was open to a reasonable misconduct panel to make a finding of misconduct if W80's honest, but mistaken, belief that his life was threatened was found to be unreasonable.
"That conclusion was soundly based in law on the proper and plain meaning of the relevant regulations and the (College of Policing's) Code of Ethics."
Officer W80 has seven days to decide whether to appeal to the Supreme Court, the court was also told.
IOPC director general Michael Lockwood described the Court of Appeal's ruling as "an important legal decision for maintaining public trust and confidence".
"The examination of serious incidents such as this in a disciplinary hearing ensures transparency and public scrutiny of the circumstances," he said.
Following the ruling, the Met Police said it was continuing to offer support to W80, their family and wider colleagues.
Deputy Assistant Commissioner Matt Twist said their firearms officers "know and accept their actions will be highly scrutinised but no doubt they will be disappointed by today's judgement".
The National Police Chiefs' Council lead for armed policing, Ch Con Simon Chesterman, described the judgement as "disappointing".
He said that while the scrutiny of police actions was "hugely important", it was equally important that "the challenges faced by officers are recognised and they are treated fairly by those judging their actions with the benefit of hindsight".