londoninvestor wrote:BobGe wrote:Going back to the advice: "Our IT department have suggested updating the time zone on your PC to (UTC+00:00) Dublin, Edinburgh, Lisbon, London and not GMT..." Can anyone find a difference between UCT+00.00 and GMT?
The key is in the "Dublin, Edinburgh, Lisbon, London".
So "(UTC+00:00) Dublin, Edinburgh, Lisbon, London" doesn't mean "UTC+00:00 all year round", which would indeed be for all intents and purposes identical to GMT.
It means "UTC+00:00 as the base, but modified by the daylight saving time rules of the UK, Ireland, and Portugal". That means UTC+00:00 in winter, UTC+01:00 in summer.
To be fantastically pedantic, you could argue that Dublin shouldn't really be in here. Ireland has the same time as the UK and Portugal in practice, but has a different legal definition. Instead of having a standard time of UTC+00:00 which moves forward in the summer, Ireland has a standard time of UTC+01:00 which moves backward in the winter. "Winter" here being the exact opposite of the UK and Portugal's "summer" - every EU country that applies a time adjustment does so at exactly the same time of year: forward at 02:00 UTC on the last Sunday of March, backward at 02:00 UTC on the last Sunday of October.
The simple answer (of course) is: If the PC was set to GMT, rather than (UTC +00:00) Dublin, Edinburgh, Lisbon and London with Daylight Saving Time, it would be out by one hour during BST. Whew!