Regular correspondent Bob has another teaser for you. What is this caterpillar? He'd really like to know. Answers on a postcard please. Or a comment, or a tweet, or an email. Thanks!

Update: @Max_Wildlife on Twitter responds with typical speed to suggest it is the caterpillar of the Old lady moth but comments that he'd be surer if he knew what plant it had been found on. I'll ask Bob…

Update 2: Bob says he found it on Swiss Chard (as per the first photo). John's comment below wonders if it is a Large yellow underwing moth caterpillar. For Bob's sake I hope not, as it is described as "one of the most hated of garden pests".

Update 3: Max has refined his opinion and now almost agrees with John – but reckons it's a Lesser yellow underwing. The crucial difference seems to be that the Lesser feeds on foliage (like Bob's Swiss Chard) whereas the Large eats through the base of herbaceous plants and hence is known as a cutworm. Personally I'm going to go with Lesser and call it case closed.