Oxford time

As a result of the rotation of the Earth, the mean solar time of places that differ from each other in longitude deviates from one another; this deviation amounts to four minutes of time per degree difference in geographical longitude, or one hour per fifteen degrees.

[3] Out of tradition, local Oxford mean time is still used as a basis for some events in the city, as opposed to the more common Greenwich Mean Time (GMT) defined by the Greenwich meridian.

The consequence of this is that, when measured by a clock set to GMT, events begin five minutes after the specified time.

This applies, for example, to lectures,[4] the closing of college doors[5] and services in Christ Church Cathedral.

[6] Despite superficial similarities, the Oxford period, therefore, has a historical background that differs from that of the academic quarter used in some continental European universities.