Found in my garden at the end of September, a very impressive caterpillar also know as “Rusty Tussock”. Wish it was a bigger and could be trained to do some household chores, like dusting perhaps! This webpage (amongst others) has some more information: https://www.naturespot.org.uk/species/vapourer . The photos of the egg stage look very similar to those I found on a piece of plastic sheet last autumn; shown in photo below with caterpillars emerging in May 2020:

I wonder if these are Vapourer caterpillars, they look hairy enough. If so, and since they were only a few metres away from the more developed caterpillar, maybe it was part of this batch.

Another moth caterpillar with a raised “tail” is a Pale Tussock; see earlier post, and more info here.