People who work irregular hours are also entitled to paid holiday, no matter what contract they are on.
Every hour they work counts towards their holiday entitlement, up to the full time working week (normally 40 hours).
You must average out their worked hours over the previous 52 weeks to find out how much holiday entitlement they have in that month.
You are no longer allowed to use 12.07% or a 3 month average (changed in April 2020).
Staff also have other rights when it comes to holiday pay. For example, they accrue holiday entitlement while off work sick or during maternity, paternity and adoption leave.