Actually it's not the strongest beer. The same company makes a 40% abv IPA called "Sink the Bismarch".

http://www.brewdog.com/sink_the_bismark.php

Sarge

P.S. Almost all my homebrews run between 9% to 13% abv. Got a nice Strong Scottish Ale at 11% in the keg right now. Right next to that is another keg full of 5 gallons of a 12.% abv barley wine ale of my own recipe. Ok, I'm getting thursty!