Employment laws have been around for many years now and some are specific to employees and others to employers. If you are an employee or an employer you should be aware of the laws that affect you and your business (if applicable).
If an employee feels that they are not being treated fairly at work or that they are having to work in surroundings that are not fit then they should first approach their employer. Ideally this should be done in writing and records kept of all communication. In many incidences this is all it takes to sort out an issue, but should you not be satisfied with the outcome then is advice you can seek about how to take things further.
ACAS is a company that specialises on employment rights, they give free and impartial advice and if they cannot help you they will put you in touch with the right people who can.