Red Admiral Butterfly

A late-season red admiral butterfly, Vanessa atalanta (Lepidoptera: Nymphalidae).

And from back in May, here is what I think is a red admiral caterpillar, on a stinging nettle (Urtica dioica):

There is seems to be quite a lot of variation in the colour of the caterpillars of this species but here is an example of the above reddish-brown-with-yellow-spikes colour scheme.

Photo taken in Whiteknights Park, Reading University grounds, Reading, UK, on 2010-05-23.