Celebrated champion Sebastian Vettel's world title is in doubt as Ferrari are considering an appeal to the FIA over what may have been an illegal manoeuvre by the Red Bull driver in Sunday's Brazilian Grand Prix.
Footage on YouTube appears to show Vettel overtaking Toro Rosso driver Jean-Eric Vergne under yellow flag conditions.
Watch the video:
Overtaking is outlawed under such conditions and a 20-second penalty may be handed out retrospectively, which would demote Vettel to eighth place and see Ferrari's Fernando Alonso crowned world champion by a point.