I don't think Thaksin can be extradited from the UK to Thailand as I don't think there is a mutual treaty in place, but if this episode goes as it looks likely to go then Citeh fans are going to be very, very sorry that this man was ever allowed to get his hands on their club.
He can be extradited, because there is indeed a treaty in place, and at the moment the UKG recognise the democratically elected government of thailand.
This is what makes it all very interesting to see how things will proceed! If the Thai Government ask for extradition it is very very difficult to see how the UKG can refuse! That, however, is a big if, and one that i assume thaksin feels won't happen.
But funny things have happened recently with the judiciary over here in thailand, and all for the better.
I think things are going to get very hot under the collar for thaksin.

