"On leave" may also be a euphemism for an officer being suspended. It's not going to be on an email reply to someone outside the Service that "this officer has been suspended" is it?
Omitted from the mansplain above.
Suspension can happen where there is an investigation of a public complaint or conduct matter, or where there is an allegation of misconduct or gross misconduct under the Police (Conduct) Regulations 2020 and it's thought to be in the public interest to suspend.
Not every complaint brings a suspension, there's criteria to be met.
The officer may take annual leave during this time, if the request is cleared with Professional Standards.
The suspension should be regularly reviewed, usually, every four weeks.
The officer should be kept informed, as should the officer's representative.
Suspension is to aid the investigation, it's not a punishment nor a suggestion of guilt. However, the findings of the investigation may lead to further action.
During the period of suspension, the officer is usually required to stay away from police premises, to not discuss the case with other officers apart from the nominated representative, and the officer has no police powers during this time.
To be very clear, I'm talking in general terms here, I'm not saying this particular officer has been suspended.
However, it's a possibility not to be ignored.