In message , at 22:11:13 on
Mon, 23 Aug 2004, Peter Sumner
remarked:
Meanwhile, they are wrong to imply that UTC is the legally accepted
time; unless someone has deliberately "dumbed down", for their Homepage,
the choice between UT0/UT1 and called that UTC.

Yes, but the difference between the different UTs is not relevant is
it. UTC is currently about 500msec away from UT1 and the difference is
changing as we speak. UT0 varies from UT1 according to where you are
on earth, UT2 and UT1r are smoothed versions of UT1. UTC advances
smoothly, a handy feature for measuring intervals - UT does not.

UTC is the time we use in the UK, our computers, our clocks and our
timetables all use it. Legislation still refers to GMT and this
introduces an ambiguity. Does getting to the legal time mean
correcting the time shown on the most accurate clocks we have?

Yes, unfortunately. Thankfully, there are few *legal* reasons for
knowing the time that require high precision. As this is uk.transport,
one could refer to the "10 minutes" by which trains are officially
counted as late as an example.

I can't see any dumbing down on the NPL pages - where do you see this?

Well, if you don't believe that their use of "UTC", as discussed, on
their home page is "dumbing down", then it's simply a mistake. I was
giving them the benefit of the doubt, ymmv.

The obvious thing for them to do is to briefly discuss the tensions
between the law, UT1, their clocks and UTC.
--
Roland Perry