British Summer Time
E8401
British Summer Time is the daylight saving time observed in the United Kingdom, during which clocks are set one hour ahead of Greenwich Mean Time to extend evening daylight in the summer months.
All labels observed (5)
| Label | Occurrences |
|---|---|
| British Summer Time canonical | 1,675 |
| British Summer Time (DST) | 4 |
| British Summer Time (seasonal) | 2 |
| British Summer Time (in the United Kingdom context) | 1 |
| Western European Summer Time | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T37040 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: British Summer Time Context triple: [United Kingdom, timeZoneDST, British Summer Time]
-
A.
Greenwich Mean Time
Greenwich Mean Time is the mean solar time at the Royal Observatory in Greenwich, London, historically used as the world’s primary reference for timekeeping and the basis for Coordinated Universal Time (UTC).
-
B.
Europe/London
Europe/London is the time zone used in the United Kingdom, observing Greenwich Mean Time (GMT) in winter and British Summer Time (BST) in summer.
-
C.
Chile Summer Time
Chile Summer Time is the daylight saving time period used in Chile, during which clocks are advanced one hour to provide extended evening daylight compared to standard time.
-
D.
Central European Time
Central European Time is a standard time zone used by many countries in central and western Europe, typically one hour ahead of Coordinated Universal Time (UTC+1).
-
E.
GMT
GMT (Greenwich Mean Time) is the mean solar time at the Royal Observatory in Greenwich, London, historically used as the international civil time standard and the basis for modern time zones.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: British Summer Time Target entity description: British Summer Time is the daylight saving time observed in the United Kingdom, during which clocks are set one hour ahead of Greenwich Mean Time to extend evening daylight in the summer months.
-
A.
Greenwich Mean Time
Greenwich Mean Time is the mean solar time at the Royal Observatory in Greenwich, London, historically used as the world’s primary reference for timekeeping and the basis for Coordinated Universal Time (UTC).
-
B.
Europe/London
Europe/London is the time zone used in the United Kingdom, observing Greenwich Mean Time (GMT) in winter and British Summer Time (BST) in summer.
-
C.
Chile Summer Time
Chile Summer Time is the daylight saving time period used in Chile, during which clocks are advanced one hour to provide extended evening daylight compared to standard time.
-
D.
Central European Time
Central European Time is a standard time zone used by many countries in central and western Europe, typically one hour ahead of Coordinated Universal Time (UTC+1).
-
E.
GMT
GMT (Greenwich Mean Time) is the mean solar time at the Royal Observatory in Greenwich, London, historically used as the international civil time standard and the basis for modern time zones.
- F. None of above. chosen
Statements (49)
| Predicate | Object |
|---|---|
| instanceOf |
daylight saving time
ⓘ
time standard ⓘ |
| alsoKnownAs | summer time in the United Kingdom ⓘ |
| appliesDuringMonths | late March to late October ⓘ |
| appliesDuringSeason | summer ⓘ |
| basedOnTimeZone | Greenwich Mean Time ⓘ |
| category |
Daylight saving time by country
ⓘ
Time in the United Kingdom ⓘ |
| clockChange |
clocks set back 1 hour at end
ⓘ
clocks set forward 1 hour at start ⓘ |
| coordinatedWith | European Union summer time rules (historically and currently aligned) ⓘ |
| country | United Kingdom ⓘ |
| effectOnLocalTime | shifts civil time one hour earlier relative to solar time ⓘ |
| endRule | last Sunday in October ⓘ |
| endTimeOfChange | 02:00 BST ⓘ |
| followedByTimeZone | Greenwich Mean Time ⓘ |
| followsTimeZone | Greenwich Mean Time ⓘ |
| governedBy |
Summer Time Act 1916
ⓘ
Summer Time Act 1916 ⓘ
surface form:
Summer Time Act 1925
British Summer Time Act 1972 ⓘ
surface form:
Summer Time Act 1972
subsequent statutory instruments of the UK Parliament ⓘ |
| introducedBy |
UK government
ⓘ
surface form:
United Kingdom government
|
| introducedInYear | 1916 ⓘ |
| legalTimeOf | United Kingdom ⓘ |
| namedAfter | British Summer Time Act 1972 ⓘ |
| observedBy |
Crown dependencies
ⓘ
United Kingdom ⓘ |
| offsetFromGMT | +1 hour ⓘ |
| offsetFromGreenwichMeanTime | +1 hour ⓘ |
| purpose |
extend evening daylight
ⓘ
reduce energy consumption ⓘ |
| relatedConcept |
Coordinated Universal Time
ⓘ
Greenwich Mean Time ⓘ daylight saving time in Europe ⓘ |
| shortName | BST ⓘ |
| startRule | last Sunday in March ⓘ |
| startTimeOfChange | 01:00 GMT ⓘ |
| timeNotation |
12-hour clock
ⓘ
24-hour clock ⓘ |
| timeZoneAbbreviation | BST ⓘ |
| typicalEndHourLocal | 01:00 UTC ⓘ |
| typicalStartHourLocal | 01:00 UTC ⓘ |
| usedInRegion |
Channel Islands (crown dependencies)
ⓘ
surface form:
Channel Islands
England ⓘ Isle of Man (crown dependency) ⓘ
surface form:
Isle of Man
Northern Ireland ⓘ Scotland ⓘ Wales ⓘ |
| UTCoffset | UTC+1 ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: British Summer Time Description of subject: British Summer Time is the daylight saving time observed in the United Kingdom, during which clocks are set one hour ahead of Greenwich Mean Time to extend evening daylight in the summer months.
Referenced by (1,683)
Full triples — surface form annotated when it differs from this entity's canonical label.
this entity surface form:
Western European Summer Time
subject surface form:
London
subject surface form:
Cambridgeshire
subject surface form:
Lichfield
subject surface form:
Prime Minister's Office (United Kingdom)
subject surface form:
London Stansted Airport