Cruelty to animals.
As to the recent riots in London - it put me in mind of the L.A. riots during the Rodney King incident. I was living in LA at the time and I remember how frightening it was.
I was working in down town LA and when the verdict was announced my employers closed the office and told us all to the get the hell out of dodge! The following days were scary. Curfews were imposed and if you were caught out on the streets after night fall with out a very good reason you could be fined and/or carted off to jail. The national guard was called in and I remember looking out of my apartment windows and seeing guards men in full riot gear patrolling the tops of surrounding buildings with machine gun!
I have to agree with Sue as to a suitable punishment. Make them clean the streets and rebuild the communities they've destroyed.
Same question: What do you think is a suitable penalty for those engaged in the London riots?