I've always been astonished at the litter issue in the UK. When I first came here 20 years ago, one of the first things that struck me was the rubbish everywhere. It's not a new thing.
I don;t think festivals are at all to blame. There are loads of bins at Glastonbury, and the environment is much more in your face as you are outdoors most of the time. Many people are really conscientious about it.
Bins get full and overflow. A majority (guess) of the rubbish around here, central London, is from full bins, or bins that haven;t been emptied, left full, and covered over. So no bin. ANd of course, councils are cutting collection services everywhere.
I grew up with a "no littering" ethos drummed into me. There was a strong public message, and lots aimed at children - in NZ we were "Tidy Kiwis" from a very young age. I've never seen a similar consistent campaign in UK. I don't know if I can remember one public campaign about litter here.
I would never dream of littering - I think in big part to the constant messages that it was unacceptable and anti-social. And it is lovely, uplifting and good for us all to have clean streets, beaches and countryside.
I always ask my DC to put their own rubbish in the bin, or a pocket or bag they have is no bin is around. They give it to me as a last resort. Most of their friends, that I have seen, give their rubbish to their parents, or just drop it. At the park after school recently, a Mum just sat there and watched as her DS threw 3 pieces of snack/drink litter on the ground. (yes we watched and tutted lightly :)) I'm always seeing litter thrown out of cars, or dropped by pedestrians, people in parks etc - this is more of a problem IMO than festivals.
Oh and it goes hand in hand with fly tipping. THere is rubbish dumped outside our flats nearly daily - either by residents (rarely) and other residents close by. I hate it. I've come to think they want the rubbish out of their small flats which is understandable - there is no where to leave it unless it is a rubbish collection day, so they dump it "out of sight" - at our flats. :(