Geez, no matter how many times this question comes up, we always get the "at my works you'd be entitled to this amount of holiday" type of answer. A fat lot of help that is to anyone. The true answer can only given given related to the statutory minimum amount - you may get more holiday if your T&Cs allow for it. The following is copied from the Direct Gov site.
"There is a minimum right to paid holiday, but your employer may offer more than this. The main things you should know about holiday rights are that:
•you are entitled to a minimum of 5.6 weeks paid annual leave (28 days for someone working five days a week)
•part-time workers are entitled to the same level of holiday pro rata (so 5.6 times your usual working week, eg 22.4 days for someone working four days a week)".
So your answer (in hours) will depend on how many hours a full-timer at your works does. If a full-timer works a 40 hour week, he/she would get at least 28*40/5 hours holiday per annum (224 hours holiday per annum), including public holidays. In which case you would get 28*20/5 hours holiday or 112 hours per week. You will have to pro rata your holiday if a full-timer works a different number of hours per week.
If you are a part-timer who works a different shift length for different days of the week it is ESSENTIAL that your holiday is calculated and taken in hours, not in days.