> When the clock is turned back at the end of Summer Time, does 
> the time then become 00:00:01 of the same day or is it set 
> back to midnight of the previous day?

I believe that British Summer Time always ends at 3 am, and the clock is set
back to 2 am.

(I heard a little story once, if Tommie will allow me to tell it, of someone
who was up late one Saturday night coding. At 3 am he got a Windows pop-up
"do you want to put the clock back?". Clicks OK, keeps working. An hour
later, at 3 am, another Windows pop-up, "do you want to put the clock
back?".... Don't these guys test anything?)

Michael Kay
http://www.saxonica.com/