Thames Valley Police is appealing for witnesses after a serious assault in Didcot.
Police were called by the ambulance service at 6.18am this morning after a 50-year-old man had been found with a serious head injury in a property in Park Close, Didcot.
The ambulance service was called by another resident of the house.
The man has been taken to the JR2 Hospital, where he remains in a critical condition.
The fire service are also at the address as officers and ambulance staff smelt a strong smell of a substance, believed to be petrol.
No properties have been evacuated.
Det Insp John Turner said: “The investigation into this incident is at a very early stage, and we have not established how the man came to be injured, however we are treating it as an assault at this time.
“I am keen to speak to anyone who saw any suspicious activity in the area or who has any information which may help officers with our enquiry.”