After being caught on camera in Vietnam this week, the next sighting pegs the Pre as in London, UK.  Twitter user utku spotted what sounds like a field tester using his Pre on the Tube; however when approached the user became highly secretive.

“So I went to the guy and said “Ooh, I see you have a Palm Pre.” On which the guy got very secretive and was like “Er, year it’s for work.” and put it away and turned away” utku, Twitter

Now, we’ve heard of at least one CDMA Pre being bought in the US, activated via a workaround and used solely as a WiFi device.  However if this was such a case, we can’t imagine a reason for the owner to be so cautious with the smartphone; rather, we’d expect them to be pleased to show off their modified toy.

This could indicate, then, that a UK carrier (or Palm’s UK arm) are currently testing the GSM version of the smartphone, in advance of the European launch.  That’s only been narrowed down to “second half of 2009″, but considering the first in-the-wild shots of the CDMA Pre began to emerge just two months before the official launch, the GSM model may be closer than we expected.

[via PreCentral]