Having a criminal record does not necessarily mean you won't be hired, because if there's a pardon in process, it would go to the character of the individual and whether you could hire them.
I'm giving you an evasive answer to the extent that I know we've hired people who may in the past have had a conviction, but they've received a pardon. It might have been for assault or something like that, and it happened a number of years ago, when they were 16 or 17. They're now 28, they have a whole series of life experiences behind them, and they can demonstrate integrity and character.
Some things are certainly going to preclude you from going into policing, but I wouldn't want to be so specific as to say you could never do that.