London Police Service says they found a man seriously injured after responding to a disturbance call in the area of Horton Street East and Clarence Street on Saturday night.
The man, 56, was then transported to hospital by EMS where he remains in critical condition.
Police were seen investigating the Horton Variety store in the area this morning.
The identity of the victim has not yet been released.
Police are investigating this as a serious assault and urge anyone with information to come forward.