Set the timer to 139 minutes

How to use the online timer

You start the countdown, put your phone away and settle into a West End matinee, expecting the performance and interval to fill two hours and nineteen minutes. It gives you a clear reference for the likely finish while your attention stays on the stage rather than the clock. The running time can still shift slightly with the production and the length of the interval.

Once the lights go down, the countdown may sit in a background tab while you use another app or leave the screen locked. Returning to the tab should show how much of the planned theatre visit remains. If the browser page is closed, or the device sleeps deeply enough to stop browser activity, the end sound may not mark the matinee’s expected finishing point.

During a performance, a phone is easier to keep with you, but it should stay silent and out of sight in the auditorium; rely on vibration only if that is suitable for the venue. A laptop is less practical in a theatre seat, though it can keep the countdown visible for someone waiting elsewhere. Either way, allow a little flexibility for applause, leaving the auditorium and the busy pavements around Theatreland.