A 24-spot ladybird, Subcoccinella vigintiquatuorpunctata = Subcoccinella 24-punctata (Coleoptera: Coccinellidae). This species feeds on vegetation rather than aphids. In the above photo you can see where the ladybird has chewed away a small part of the leaf surface. The following photo from 10 days later shows one which has chewed a much larger area:
First photo taken in the field below Chazey Wood, near Caversham, UK, on 2012-05-08. Second photo taken in Whiteknights Park, Reading, UK, on 2012-05-18.