And it seems to be vastly expanded over the previous (US only) version.
Get local business listings when you're on the road and want to find a place to eat. Obtain driving directions to get from point A to point B without having to ask for directions. Get quick answers to straightforward questions. Compare online product prices with ones you find on the high street. Look up dictionary definitions to expand your vocabulary or prove a point. Solve math problems such as converting to metric units.
BTW, this is either a free service, or they are breaking UK rules by not informing you of the cost per message :)
Actually I have found Google SMS UK to be slightly unreliable at times. Sometimes I do not get the result for 24 hours and other times do not receive it at all. Of course this may just be down to my provider and not Google.