What is UTC?¶

UTC is Coordinated Universal Time.

It is the common time standard used by many computer systems, networks and cloud services so that events can be recorded consistently across different locations.

Avoid this assumption: That UTC is simply another name for United Kingdom local time. It is not always the same.

The United Kingdom uses UTC during Greenwich Mean Time, usually in the winter. During British Summer Time, local UK time is one hour ahead of UTC.

For example, 10:00 UTC is 10:00 in the UK during winter but 11:00 during British Summer Time.

UTC does not itself change for daylight saving. That stability makes it useful for technical systems and cross-border records. A server in one country and a cloud platform in another can both record events against the same reference standard.

UTC timestamps may be marked with a “Z”, the word UTC or an offset of +00:00. But investigators should still confirm the field definition rather than relying only on appearance.

Some systems store UTC internally and convert it to local time when displayed. An export may contain the stored UTC value while a screenshot shows the converted local time.

Investigators should preserve the original value and note whether it is stored UTC, displayed UTC or converted from another zone. When comparing with local records such as CCTV or witness accounts, apply the correct daylight-saving rule for the relevant date.

Operational takeaway¶

UTC is a stable global time standard, but it must not be confused automatically with local UK time because local time may be one hour ahead during British Summer Time.