"Dr John Stockton" wrote in message
...

Possibly so. But I was asking for references or evidence; hard details
- not limited to London or UK, BTW.

Broadcasters do this all the time - they use clock times that run 06:00:00 -
29:59:59, except one day of the year which finishes at 30:59:59. See, for
example:

http://www.atruk.co.uk/BARB/BARB2002LSP01.doc

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