C.T.O.
Where a full time Constable or Sergeant works overtime, it is the choice of the officer who works the overtime whether the overtime should be taken as pay or CTO. It is not the choice of management. The officer must make that choice in that pay period, which I interpret as before the end of the month. The pay or CTO should be paid at the correct rate of double time, time and a half, or time and a third.
A manager can ask you to voluntarily work overtime for CTO. You can though decline to do so.
You should be allowed to take that CTO as time off within a 3 month period. If you are not allowed to take the CTO within the 3 month period then you are entitled to be paid for it instead - indeed it should be automatically paid into your salary.
You can be refused a request to take CTO due to the exigencies of the service - such as a known event. Basically if you ask for time off at such a key time and that request if refused, you are still entitled to be paid for any CTO not taken off within the 3 month period.
Local arrangements in Lancashire show CTO as a total on DMS. Historically CTO has been carried over for several years. These are local arrangements including the 120 unit limit and they exist outside Police Regulations.
You cannot be lawfully told to take time off as CTO (ie. a manager cannot tell you that you have to take CTO on a certain date), although you can be asked to reduce your CTO levels.
If you encounter problems with CTO please contact your local Federation Representative.
The above is covered in Regulation 25 (see also Annex G) of the Police Regulations and Determinations 2003.