Scotland Yard chief Sir Mark Rowley says firearms officers would rather face terrorists than regular criminals because there is less risk of a legal backlash.
Metropolitan Police Commissioner Sir Mark called for urgent reforms to make things fairer for officers facing years of scrutiny as they carry out duties keeping the public safe.
Six terrorists have been shot dead in four major incidents in London since 2017, without any firearms officers being arrested or subjected to lengthy investigations by the police watchdog, The Sun reports.
Sir Mark said: “One thing that’s really startled me is I’ve had some of our firearms officers say to me they would rather end up confronting on the streets a well-trained terrorist than a gangster.
“Because even though they would face far more personal danger with the terrorist, they believe they’d get a fair hearing in terms of the legal processes that follow.
“Whereas with a gangster, they feel that campaign groups can influence accountability in a way that leads to something that’s unbalanced and lasts forever.”
Ex-Home Secretary Suella Braverman announced a review after scores of armed Met officers stood down after a colleague was charged with murder.
Another - codenamed W80 - is still waiting to learn if he will face a gross misconduct panel eight years after shooting dead Jermaine Baker, 28, during a foiled plot to snatch two prisoners from a van near Wood Green Crown Court.
A lengthy legal battle between the Independent Office for Police Conduct and the Met has been ongoing even though the marksman was cleared by the Crown Prosecution Service and a public inquiry.
Sir Mark said: “An inquest has looked at that shooting and the inquiry was content with integrity.
“Yet the IOPC have mandated he is now going to go on a gross misconduct hearing and we are eight years post-events.
“Even regardless of the rights and wrongs of the IOPC decision, to have someone’s career in suspended animation with that stress for eight years is not acceptable.”
The review will also look into police drivers involved in fatal pursuits and crashes.
Sir Mark Rowley described the prosecution of Pc Paul Fisher, 46, who crashed while driving to the scene of a terror attack as “appalling”, adding: “Thank god for the common sense of British juries.
“No other country in the world would haul one of its most highly trained officers before a court for responding to one of the most serious incidents we can deal with and doing their utmost to preserve life.”