There have been ugly scenes in central London ahead of the G20 summit. Demonstrators clashed with riot police in Britain’s financial centre. The Bank of England was a flash point as was a branch of the Royal Bank of Scotland, where windows were smashed.Rescued by the government, the RBS has become a lightning rod for public anger over banker excess, blamed for the financial crisis. Some police and protesters were injured in the clashes. More than 20 arrests have been made, but street battles don’t tell the full story. Of the thousands marching, many did so peacefully, eager, above all, to get their message across. “We are going to challenge capitalism. We are going to challenge the G20,” said one man. “We want to point out that there are other ways to work in the world than the way they are doing it because they have completely screwed up. Capitalism is dying. It is eating itself.” Anxious for the G20 to tackle global warming, environmental activists have also been protesting. Sporting a green wig, one woman dressed as a mermaid. “I am here because I care very much about rising sea levels and climate change and obviously, being a mermaid, I am very worried that my natural habitat is going to disappear soon,” she said. The plight of the Palestinians was highlighted by the Stop the War Coalition, with a gathering outside the US Embassy and a march to Trafalgar Square. One way or another, demonstrators have succeeded in shining the spotlight on their G20 demands.