Discrimination means treating a person unfairly. The Equality Act 2010 makes it illegal to discriminate against someone because of their protected characteristics. Discrimination can either be direct, or indirect.
Direct discrimination is intentionally treating a person less favourably for example, telling someone that they cannot access a building because of their race or ethnicity. Indirect discrimination is when a system, policy, or protocol does not appear to be discriminatory but has the unintentional effect of causing discrimination. For example, a workplace saying that a man cannot wear jewellery in the workplace and not providing an exception for jewellery which is an expression of a religion, such as Kara which are worn by some Sikhs.
Under the Equality Act you have a right to complain if you feel you have been discriminated against either directly or indirectly in accessing a service.