But the judgment in the landmark Supreme Court ruling in Chief Constable of the Police Service of Northern Ireland and another v Agnew and other & UNISON overrules holiday pay case law operating since 2015. As set out above, this prevented tribunals from considering deductions where there had been a gap of three months or more between a series of similar underpayments for an employee. UNISON says many UK workers could be entitled to thousands of pounds taken unfairly from their pay. Many workers will now be able to challenge ongoing linked underpayments in their wages, it added, even if there is a gap of three months or more since the last time this happened.