If you are contracted to work 25 hours a week and work over that time are you entitled to be paid time-and-a-half?
Under the Part-Time Workers’ Regulations people who work less than the normal full-time hours are only entitled to the same hourly rate of overtime pay as comparable full-time workers once they have worked more than the normal full-time hours. However it’s possible there’s a different arrangement in your firm, either via your employment contracts or through custom and practice. If you were asked to work extra hours you should have asked the rate of pay if it’s not clear in your contract or from what your colleagues receive in this situation. If you just stayed on without being asked it could be that you’re not entitled to anything.