We break down the key storylines behind Chris Froome's doping test from the Vuelta. He went over the limit for Salbutamol. Now, Froome and Sky have a chance to explain themselves, but a pall of doubt has been cast over his four Tour wins and that Vuelta victory. We speak with Andrew Hood who has insider knowledge from an anti-doping expert and a lawyer. This is cycling's biggest story in years — stay tuned as new developments come to light.

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