All workers have a statutory right to at least 5.6 weeks' paid annual leave (that's 28 days' paid holiday if you work five days a week). Note that this statutory right to annual leave is capped at 28 days' paid holiday, which means that you are not entitled to any more than this if you work for more than five days a week.
There is a minimum right to paid holiday, your employer may offer more than this. The main things you should know about holiday rights are:
In order to qualify for the right to annual leave you need to be classed as a worker. If you're self-employed, you have no statutory right to paid annual leave.
You do not have a statutory right to paid leave on bank and public holidays. If paid leave is given on a bank or public holiday, this can count towards your 5.6 weeks' minimum holiday entitlement.
If you work on a bank or public holiday, there is no automatic right to an enhanced pay rate. What you get paid depends on your contract of employment.
If full-time workers get paid leave on a public holiday, part-timers who don't normally work on that day have the right to paid time off on another day, proportionate to the hours they work.
If you're not getting your full holiday entitlement, speak to your employer. If you have an employee representative (for example, a trade union official) you can ask for their help. Follow the procedures given in the article about sorting out work problems. If this doesn't help, you can complain to an employment tribunal (or industrial tribunal in Northern Ireland).