The vexed issue of calculating holiday pay was considered by the Employment Tribunal in the case of Brettle -v- Dudley Metropolitan Borough Council in which it considered whether truly voluntary overtime (which the employer is not obliged to offer and the employee is not obliged to work) should be included when calculating holiday pay. The Tribunal concluded that this depended on whether it amounted to "normal pay" and this would depend on the facts on a case-by-case basis. The Tribunal particularly took into account the frequency with which the voluntary overtime was worked by the claimants to determine the issue. The decision is not binding on future Tribunals and so is unlikely to be a reason for employers to change their practice. However, the decision is helpful in showing how some Tribunals may determine the issue and is a further indication that some voluntary overtime may need to be included when calculating holiday pay.