Law regarding holiday entitlement/payment

Hi,
I've worked for same multinational company for 15 years. I get paid every 4 weeks so 13 times a year. For all this time i have been given 13.99 holiday hours per pay period. This month i was only given 12.82 and when i questioned this, payroll said that they had been mistaken previously and that this was what i was entitled to from now on. Can they do this without consultation or even alerting anyone that they were doing it? This happened to the entire company too by the way.
Cheers for any replies.

Do you have a contract? What does it say about your holiday entitlement? The statutory entitlement is 4 working weeks per year for full-time staff. This is usually 20 days. Based on 8 hour work days, 12.82 hrs per pay period would equate to 20.82 days per annum.

Allowing for some roundings, it looks like someone divided the holidays into 12 monthly segments instead of by 13.

The proper way to handle this is hands up with good communication, not just hiding behind a payslip hoping no one notices. Maybe give 1 year notice that it will revert to correct system as per contract.
I've said it a few times on this site, the level of ineptitude in many payroll departments is staggering. Very often, run by people who came in as a junior admin or secretary and moved into payroll with no proper training.

I'm sure too, some employees knew about the error all along...