Public Holidays are a day's leave unless the exigencies of duty make the Force require you to work on that day. For Constables and Sergeants the compensation for working a BH remains double Time.
What if I work into a BH? If for example you are on a night shift and are required to work on into the BH you are entitled to a minimum 4 hours at Double Time and a reallocated BH. You should be notified of the reallocated date within 4 days of the notification and this would be expected to be reallocated within the following 3 months. This applies only when you have less than 8 days’ notice of the requirement. More than 8 days then the compensation is simple at Double Time for the hours worked.
For information on Moving Bank Holidays click on the link.