A 34-year-old man is in hospital with life threatening injuries after falling from a fourth floor balcony at a block of flats.
Police and ambulance crews were called to the scene at Keynsham Road in Bittern shortly after 1:30am today.
He remains in a serious condition at Southampton General Hospital.
The circumstances as to how he fell are unclear at the moment but police are speaking to local residents to help establish what happened.
A 28-year-old woman has been arrested and remains in custody.