It's interesting to see so many comments on lily beetles. I remember my excitement when I first saw one on moving to London 25 years ago. It was eating someone else's lilies and at the time I had no idea how ruinous it could be to these plants. This pretty beetle has undergone an astonishing change in Britain in the last 75 years. At the end of the 19th century, it was a very rare insect, an accidental import with horticultural good from the Continent. It remained scarce until the 1940s when it got a firm foothold in the Guildford area of Surrey. It then started to spread until it is now one of the most widely cursed garden pests.
We've been lucky this year and I have not seen a single beetle in the garden, but then we are growing far fewer lilies than a couple of years ago. I did see one earlier this year, but it was in Nunhead Cemetery. It was busy shredding a snakes-head fritillary that had obviously been planted in one of the woodland clearings.