Sir Bernard Hogan-Howe will use his final set-piece speech as Commissioner of the Metropolitan Police Service (MPS) to call for greater public support for firearms officers, who volunteer on behalf of Londoners, and their unarmed colleagues to deal with terrorists and armed criminals.
The Commissioner ordered an increase of 600 highly-trained specialist officers after the attacks in Paris in November 2015. He subsequently expressed concern about the treatment of officers involved in shootings. One officer was charged with murder and acquitted in 2015.
The then Prime Minister, David Cameron, agreed to review the legal issues, and firearms officers await the outcome.
Speaking at the Royal United Services Institute today, Tuesday, 14 February, the Commissioner will say: "When people look at what we do, there should be less suspicion and more trust".
The Commissioner will reveal that the Met deployed to incidents involving firearms on more than 3,300 occasions in 2016, without firing a single shot at a suspect. But he will also reiterate his concern over armed criminality after a year in which nearly 700 firearms were recovered by officers in London and 12 people were shot dead by criminals.
The MPS plan to increase the number of armed officers is well on track with over 400 extra officers trained or selected to date.
Officers who volunteer for a specialist firearms role face a demanding training course, which a significant number do not pass. In addition, as existing officers retire from this highly trained role, others must take their place. This means the MPS is always seeking more volunteers.
The Commissioner will say that officers are concerned at what has happened to colleagues who have had to use lethal force: "This a dangerous place to be - in two ways. We simply don't have enough people now wanting to do these jobs. The failure rate in training is high.
"Secondly, we can't afford to have officers think twice because they fear the consequences of shooting someone. That's how they get shot, or the public gets hurt or a criminal gets away with a gun."
The Commissioner will highlight comments made by Prime Minister Theresa May in an interview before Christmas in which she said officers were "unsung heroes".
He will also praise the Mayor of London, Sadiq Khan, for meeting firearms officers at the first opportunity after his election and recognising their bravery and dedication.
Sir Bernard's comments will form part of a speech entitled 'Policing the Metropolis and how policing in the future can change'.