The period of notice required to be given under a term (whether express or implied and, if express, whether oral or in writing) of a contract of employment. It is possible for the employer and employee to have to give different periods of notice. Various additional terms may be agreed, such as a requirement that notice be given in writing, or the option that the employer may shorten the notice period by making a payment in lieu of notice. The contractual notice period may be longer than the statutory minimum notice period but may not be shorter. A failure to give the required notice is likely to constitute a breach of contract.