Some terms may be implied through custom and practice in a particular trade or with a particular employer.
For example, it may become customary (over a period of time) to leave early on a Friday, or to add an extra day to a Bank Holiday. In order for an entitlement to become established by custom and practice, it must usually be long-standing, uninterrupted, automatically received, expected and well-known.
Also, sometimes the idea of custom and practice is used to interpret an express term, for example "reasonable overtime".
