The kara is circular in shape and is a symbol of restraint. In practice the kara is a constant reminder to the Sikh of ideal behaviour in the event of weakness and thus it must not be confused with jewellery.
A Kara of an adequate size and reasonable thickness should be worn. During sports activities the kara can be covered with a sweat-band.
The Kara as already emphasised is one of the five K's and should not be removed to suit the environment.
The courts have ruled that Sikhs are a "racial group" for the purposes of the Race Relations Act 1976. A rule which operated to forbid the wearing of a Kara, or resulted in, for example, the removal of a person from a football pitch who insisted on wearing one, could be alleged to constitute unlawful indirect discrimination under section 17 of the Act.
Sikh Federation (UK)