Both the employee and employer are normally entitled to a minimum period of notice on termination of employment.
Notice periods should be one of the main terms and conditions of employment and included in the employee's written statement.
It's always best to write out any form of notice to make it clear it is the termination of employment and in most cases employees should be paid their normal pay during the notice period.
Normal notice applies when employment is being terminated due to redundancy. An employment contract can be terminated at any time by either party, it could be a resignation or dismissal, redundancy or retirement. For a notice to be effective it should be in writing and specify as a minimum the date of termination.