Which end is which?

I think I am right when I say that the horned end is the tail end of this caterpillar. Not my hand, by the way! This caterpillar was seen on 1st September, on a short nature walk in connection with the Weaselhead Socety. I have seen one of these a few years ago, just outside the city, but can't for the life of me think what species it is. Can anyone help me with the ID? I had a look on Google this afternoon, but couldn't find a photo of a similar insect. Later: thanks so much, Jim, for the ID - Hyles gallii.