In Hartley v King Edward VI College, the Supreme Court has determined that a day's pay should be calculated as 1/365th of salary (rather than 1/260th) when deducting pay for teachers' strike days.

Teachers working at a sixth form college went on strike for a day. The college deducted one day's pay from their wages, calculated at the daily rate of 1/260th of their annual salary. This was based on the fact that the teachers' working days were specified in their contracts as Monday to Friday and so the daily rate was based on five working days a week (5 x 52 weeks a year = 260 working days in a year).

The teachers accepted that they were not entitled to be paid for the strike day. But they argued that, by virtue of the Apportionment Act 1870, and as their salary accrued day to day at an equal daily rate for every calendar day, the deduction should have been based on 1/365th of salary.

Following an analysis of the relevant contracts of employment, the Supreme Court held that the Apportionment Act did apply, and the sensible approach was to apportion the annual salary on a day to day basis by treating a day's pay as 1/365th of annual salary. This decision was based on findings that salary payments were made every month, even when a teacher was on holiday, and the work carried out by them was, in reality, spread throughout the year. Payment was also not limited to periods when the teacher was carrying out directed work, but included preparatory work and other duties which involved working in the evenings, at weekends and in the holidays. The Supreme Court made clear that a critical feature of the case was that the contracts were "annual contracts". If they had not been, the position would be different, and would depend on the terms of a particular contract. Unfortunately, the Court did not go on to say what is meant by an "annual contract" but the assumption is that it means a permanent, rolling, contract. It was particularly relevant that the teachers were expected to work outside of their contracted hours and days. This suggests that the outcome would not have been the same if they had been employees who worked only contracted hours/days. Employers should not assume that this decision will apply to the calculation of a day's pay for all purposes. This will depend on an analysis of the contract in question, including whether the Apportionment Act applies. However, it is possible that this decision could affect other professionals who might be expected to work outside normal contracted hours.