My wife noticed this on her trousers immediately after coming home - probably acquired after brushing past a bush. It's about one inch long, and does not move much - but when poked it will flex and appear to try to roll.

It looks for all the world like a stick - but I've googled "stick insect", and this doesn't seem to have enough (or the right kind of) legs.

We live in England, in a suburban setting. We both work in offices and don't have a lot of contact with nature.

Could it be a thorn moth larva?

Apologies for the quality of the photo; I can try to take a better one if it would help to get another angle.

What is this insect?

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    $\begingroup$ Yes, it's a Lepidoptera larvae of some kind. For instance, Biston betularia has stick-like larvae, and is found in the UK (also see Wikipedia: Bison betularia). $\endgroup$ – fileunderwater Nov 10 '15 at 20:53
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    $\begingroup$ I must say, I am impressed. This might be the most stick-like stick-like insect I have ever seen. Complete with ends that look like they broke off a longer stick. (I do not doubt it is an insect, if it moves when poked like you describe. I am really impressed.) $\endgroup$ – skymningen Nov 11 '15 at 14:13
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    $\begingroup$ I think this is an inchworm. See my answer here $\endgroup$ – рüффп Sep 13 '17 at 22:50

This appears to be an inch-worm, the larval caterpillar stage of a moth (order Lepidoptera) in the Geometridae family. According to Bugguide (my emphasis):

Larva - generally have only two pairs of prolegs (at the hind end) rather than the usual five pairs in most lepidoptera; the lack of prolegs in the middle of the body necessitates the peculiar method of locomotion, drawing the hind end up to the thoracic legs to form a loop, and then extending the body forward.

The systematics/taxonomy of this group is unclear, debated, and in flux. However, the majority of stick-like larval forms I could find seemed to be associated with the current Ennominae subfamily, which is also the largest of subfamilies in this family of moths.

Müller et al. (2019) just published the 6th volume of "The Geometrid Moths of Europe", which might be a good starting point for IDing this specimen more precisely. A book description from NHBS:

More than half of the European Ennominae, a total of 181 species, plus 21 new species for the European fauna are covered in two hardback parts (with text and plates in separate volumes), including difficult genera...

You could also keep an eye on or alternatively submit an ID request over at Wildlife Insight's Illustrated Guide to British Caterpillars.

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  • $\begingroup$ Some stick-like examples: brown-variants of Odontopera bidentata, Biston betularia, Crocallis elinguaria, Colotois pennaria, etc. I do not know this group well enough nor is your picture good enough for me to go further than I already have. If you can provide more information or better pictures, I could try to delve in a bit deeper. $\endgroup$ – theforestecologist Jul 9 '19 at 21:18

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