What's the worst that could happen to financial markets next year - hyperinflation, climate change, or the break-up of the euro? Such big-picture catastrophes are difficult to quantify, but that hasn't stopped the investment consultancy Watson Wyatt from gamely having a go - and offering some advice on how investors can protect themselves too.

Watson Wyatt's 15 extreme risks are split into three categories - economic, financial and political - and include everything up to the end of capitalism itself. They are ranked in order of importance - a ratio between their likelihood of happening and the impact they would have if they did.