A man in his 20s, from the Great Yarmouth area, is currently in Papworth Hospital after being assaulted yesterday evening.
The incident is believed to have taken place in the Havelock Road area, close to the Red Herring pub, at around 8.30 to 8.45pm.
The man was found by members of the public who contacted emergency services.
He received a puncture wound to his chest and remains in a serious but stable condition.
Detectives from Great Yarmouth CID are currently making enquiries to establish the circumstances behind the assault.
DI Matt Dyson said: 'We are in the very early stages of our investigation and would like to hear from anyone who saw an assault taking place in that area or has further information regarding the incident.'
Anyone with information should contact Norfolk Police on 101 or alternatively call Crimestoppers anonymously on 0800 555 111.
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