Using a US Tmobile Galaxy S2 in the UK

[ma3loom]

I'm hoping someone might have some experience with this prior to me visiting the UK for work. I've been over to London a few times but have always used my american sim card vs opting to purchase a pay as you go. My question is will I able to to make use of the 3G and/or data networks with my Samsung galaxy s2 from tmobile US that's unlocked.

I know my mother was unable to get anything more with 2G when I got her a tmobile US sim card this past month using the international galaxy S2.


Thoughts ideas?

Thanks