Enforcing your rights may be as easy as simply asking, or as difficult as taking a legal case as far as the Court of Justice of the European Union!
And even when the law is on your side, a vindictive boss can still do a great deal to make your life miserable, particularly if you are acting on your own. On the other hand, an employer may simply not understand the law, and welcome expert guidance on their responsibilities.
It is important to first understand why your employer is not granting you your rights. While action must be taken promptly (and there are strict time limits in place, especially in the employment tribunal), you should first be aware of all the possible consequences. This will normally mean you should take expert advice. Union members should contact their union.
Non-union members can contact employment rights advice agencies or a solicitor (though other than perhaps an initial consultation, this may prove expensive). There is no legal aid available for claims in the employment tribunal.