Tesco isn't entirely evil, of course - even Jedi knights get double Clubcard points if they promise not to whip out their lightsabers.

But no-one's as nice as The Co-op. The group last week unveiled plans to up its tree-hugging credentials by dispatching thousands of its customers and members from across the country to London for The Wave, a major climate change protest scheduled for December.

How many tonnes of carbon will the mass mobilisation create? The answer is blowin' in the wind.