Watch as SNP MP Patricia Gibson recoils in horror and wafts the air as one of her colleagues lets rip in the Commons:

Big Feartie: Which MP Gassed the Chamber? http://t.co/HMoB9QEVxr https://t.co/yGhj4RyoES

— Guido Fawkes (@GuidoFawkes) May 27, 2015

And everyone thought the chamber emptied because Clegg got up to speak…

UPDATE: The guilty culprit has been identified as Labour MP Richard Burgon.