Emergency services were called to the B & M store on Mile Cross Lane this afternoon after a man suffered a cardiac arrest.
The East of England Ambulance Service were called to the scene at 12.15pm after reports a man had collapsed.
An ambulance crew, an ambulance officer and a medical response car from the East Anglian Air Ambulance were in attendance alongside police and a fire crew from Earlham.
The man, believed to be in his 60s, had suffered a cardiac arrest and was unconscious and not breathing.
Crews, who were on the scene within three and a half minutes, were able to resuscitate the man at the scene and he was taken to the Norfolk and Norwich University Hospital for further treatment.
It is believed he is in a serious condition.
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