England uses GMT (UTC+0) in winter and BST (UTC+1) in summer, switching on the last Sunday in March and reverting on the last Sunday in October. IANA identifier: Europe/London.

Key facts about time in England

  • Timezone: Greenwich Mean Time (GMT) / British Summer Time (BST)
  • UTC offset: UTC+0 (winter), UTC+1 (summer)
  • DST: Yes, clocks advance one hour at 01:00 GMT on the last Sunday in March, and revert at 01:00 GMT on the last Sunday in October
  • IANA identifier: Europe/London
  • Capital: London

One zone for the whole of Great Britain

There is no separate timezone for England. The IANA time zone database defines a single zone, Europe/London, for the whole of Great Britain: England, Scotland, and Wales all share it, and Northern Ireland keeps the same time as well. So while you may see references to “England time,” the underlying identifier a developer uses is always Europe/London. The zone is named for London because that is where the reference meridian sits, not because England has a clock the rest of Britain does not.

The Greenwich meridian

England’s connection to timekeeping is unusually direct: the prime meridian (longitude zero, the line from which the world’s longitudes are measured) runs through Greenwich, in south-east London. Greenwich Mean Time is, by definition, the mean solar time at that meridian. The Royal Observatory was built there in the 1670s to improve astronomical observation for maritime navigation, and over the following two centuries Greenwich accumulated enough precision to become the reference British navigators sailed by.

By the late nineteenth century a single global reference was needed for charts and railways. Delegates met at the 1884 International Meridian Conference and adopted the Greenwich meridian as the prime meridian for the world, in large part because a majority of the world’s shipping already used Greenwich-based charts, so standardising on it disrupted the fewest vessels. That is why the IANA zone for Britain, and the time you read on this page, is anchored to a hill in England.

GMT is mean solar time at the Greenwich meridian. UTC, the modern global standard, is maintained by atomic clocks coordinated internationally and is held within 0.9 seconds of UT1, a measure of the Earth’s actual rotation, with leap seconds inserted as needed. For civil and everyday purposes in England, GMT and UTC are treated as interchangeable; the difference matters only to navigation, astronomy, and precise timekeeping.

The Summer Time Act 1972, Section 1, defines British Summer Time precisely. It begins “at one o’clock, Greenwich mean time, in the morning of the last Sunday in March” and ends “at one o’clock, Greenwich mean time, in the morning of the last Sunday in October.” During summer time the legal time for general purposes is one hour in advance of GMT (UTC+1). England follows this schedule in common with the rest of Great Britain; the transition dates are the same in London as they are in Edinburgh or Cardiff.

For developers

The IANA timezone for England is Europe/London. The hasDST flag is true. Transitions occur on the last Sunday in March (UTC+0 to UTC+1) and the last Sunday in October (UTC+1 to UTC+0), both at 01:00 local time. Do not look for a Europe/England identifier: it does not exist. Europe/London is the correct and only zone for England.

Sources