Custom and Practice
Terms and conditions of employment may become implied into the contract of employment if they are a custom within a particular industry or business, or a regular practice. These terms are generally not in writing but are known and agreed by all. For such a term to be viewed as a contractual requirement or entitlement the term must be reasonable, certain and notorious. This means that it must be fair, predictable, established, well known and unambiguous. Discretionary benefits, for example, enhanced redundancy payments which are not expressly written into the Written Statement of Employment Particulars or other contractual documents such as a Company Handbook, will not necessarily become implied through custom and practice simply because they have been given in the last few redundancy exercises. In the event of a disagreement an Industrial Tribunal will have the ultimate determination over whether such terms form part of the contractual entitlement.
LRA Advisory Guide Advice on agreeing and changing contracts of employment