Every worker – whether part-time or full-time - is entitled to 4.8 weeks’ paid annual leave, and for part-time workers this is calculated on a pro-rata basis. For example, an employee who works three days a week is entitled to twelve days paid holiday - their normal working week multiplied by 4.8. This is because a week’s leave should allow workers to be away from work for a week. It should be the same amount of time as the working week.
With regard to Christmas Day and Boxing Day public holidays, these can be counted as part of the statutory 4.8 weeks holiday entitlement. There is no statutory right to take bank holidays off, so unless the employees contract of employment states there is a right to paid time off for bank holidays, you are not obliged to pay your staff for these unless they take them as part of their annual leave entitlement.
The Government plans to increase the annual leave entitlement from 4.8 weeks to 5.6 weeks from 1 April 2009. If you work a five-day week, your holiday entitlement will increase from 24 days to 28 days (pro rata for part-time staff).