I think it's pretty new as the search for the url doesn't reveal any results:
http://www.google.com/search?q=%22www.google.de/base%22

There is one there now... but it was indexed today!! :-)

I remember I found www.google.FR/base in October, 26th 2005. (search the URL on Google).
But this French URL is always in english :-s

I would not consider google.co.uk/base live unless the prices are displayed in GBP and the items belong from UK.

I think you should check before making posts like these!

Hmm, maybe this was just one of those "folders work on every Google domain" kind of things, as google.it/base and google.es/base work too.

Google Base UK & DE will be lanched tomorrow :
http://www.zorgloob.com/2006/05/google-base-uk-et-de.asp

They had local-looking keywords displayed back then. Stuff like "personals DE", "tickets DE", .... So I guess it was more than that before they pulled it. I guess it just slipped out.