BBC Science Focus
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This is surprisingly hard to answer, as it depends both on how the risk is measured – per participant, say, or per event – and the availability of reliable data. But according to a 2014 analysis by Prof Sir David Spiegelhalter at Cambridge University, the UK’s leading authority on risk, mountaineering is probably the most dangerous sport, carrying a risk of death of around 1 per cent per climb. By comparison, running a marathon is around 1,000 times safer. RM