Avaaz online political campaigns targeting MPs
The internet campaigners Avaaz probably make up the biggest political organisation that most people have never heard of.
The group has more than 17 million members worldwide who bombard MPs with emails hundreds of times a day.
Their targets have included bees in Europe, oil in the Amazon, and women's rights in India. Adam Fleming reports.
More clips on our BBC website, external; 'like' us on Facebook, external page; follow us on Twitter, external or watch full programmes from the last seven days via BBC iPlayer