Look what we found crawling across our lawn today.
Isn’t he extraordinary? He stayed just like this, reared up like some prehistoric mini-dinosaur, no doubt in an attempt to make us fear for our lives. He needn’t have worried – we certainly weren’t about to eat him.
Fortunately, given his size (about the thickness of my ring finger and almost as long) he’s not a garden pest. I discovered from the outstandingly good identification site UK Moths that he’s an Elephant Hawk Moth caterpillar, and eats rosebay willowherb – which, owing to the fact that I’m seriously behind on the weeding at the moment, I happen to have a patch of at the end of one of my borders. So off he went to feast on my weeds till he turns into a lovely big moth with pink-striped wings. Who knows – if he finds another big pink-winged moth I might I no longer have a willowherb problem. Now that would be a result.
Sally Nex 
I like the weed, the worm, and the winged one. You have a beautiful life cycle going there.
My absolutely number one favourite caterpillar. And the moths are staggeringly beautiful with pink and olive green markings.They eat fuchsias and Zauschnerias, as well as several species of willoherb – but I wouldn't begrudge them that. They're never around in big enough numbers to be pests. Besides, some fuchsias are better eaten than seen!Your jumbo was almost certainly done feeding, for now, and would have been trundling off to pupate, probably in some loose soil somewhere. He or she will hatch in early summer next year.
oh thanks Nige, that's put my mind at rest. I went down to check on him after I'd written this post and couldn't see him anywhere, and no sign of willowherb being eaten either. So he's probably already burrowed down into the ground (which is quite loose around there) and is hatching into a moth as we speak. Note to self: do not weed in this spot, even if you do get around to it before reaching retirement age.And I share your views on (most) fuchsias 😀
This one looks like it needs a hookah and a silk smoking cap.