In message , at 17:28:52 on
Sat, 21 Aug 2004, Peter Sumner
remarked:
The official time in the UK is maintained by the NPL and it ticks
atomic seconds in UTC.

This is *a* time that is maintained by the NPL.

This is what happens in practice as you can tell by the addition of
leap seconds, which show plainly as an extra 'pip' in the time signals.
If we were using GMT these leap seconds would not be required. For
pedants there is a good explanation at
http://www.npl.co.uk/time/leap_second.html.

And even more detail at:

http://www.wordiq.com/definition/Universal_Time:

Our legislators have mistakenly ignored this and still pretend that
GMT is in use.

Whether a mistake or not, the fact they have ignored the need to make a
change means that Official Time is still UT1.

Not that the maximum error of 0.9 sec makes much difference to the man
on the Clapham omnibus

We can at least agree that 0.9sec is the biggest difference between the
various times.
--
Roland Perry