Thorgrim the Dwarf King, Grimgor Ironhide and "Long One" the Troll were walking home one Christmas after a night out on the Town. They all stopped to take a leak over London Bridge into the river.
On popping their unmentionables out of their trousers...
Thorgrim looked at Grimgor and said "Strewth Lad, it's mighty cold !"
Grimgor: "ouch, so is the water !"
Long One : "Yep, it's deep too !"
That's it, the best I have for now :)