Emergency services were called at 9.50pm last night (12/10) to reports of a two-vehicle collision involving a silver Subaru people carrier and a white heavy goods’ vehicle.
The collision occurred near to the railway overbridge just to the west of Oxford.
The force received multiple calls from the public and responded quickly.
Very tragically, three children, a four-year-old girl, an eight year-old girl and a six-year-old boy and one adult, a 29-year-old woman, were pronounced dead at the scene.
Two other passengers in the Subaru, a 30-year-old man and an 18-month-old girl, have been taken to the John Radcliffe Hospital in Oxford, where they both remain in a critical condition.
The driver of the HGV, a 56-year-old man, suffered minor injuries.
Senior Investigating Officer Sergeant Dominic Mahon, of the Serious Collision Investigation Unit, based at Bicester, said: “We are in the very early stages of our investigation into this incredibly tragic incident that has resulted in the deaths of four people from the same family.
“I would appeal to anybody who was driving in the area at the time of the collision and witnessed what happened to please contact 101, or make a report online, quoting reference number 43200321914.
“I would also urge anybody who has dash-cam footage of the incident or either of the vehicles just prior to the incident to please not share this publicly, but contact police with this detail.
“I would ask the public and media to please not speculate as to the cause of this horrendous incident. We will leave no stone unturned to ascertain what has caused this tragedy.
“The next of kin of the family have been made aware and are being supported by specially trained Family Liaison Officers.
“The thoughts of all of us at Thames Valley Police, along with our partners who have assisted at the scene or at the hospital, are with the families at this incredibly difficult time.
“I would like to also pay tribute to our officers, first responders and medical professionals, who dealt with this collision.
“Our officers and colleagues from the other emergency services were dealing with an extremely upsetting scene, and I would like to thank them for the work that they carried out overnight.
“Our officers remain at the scene and the A40 will remain closed in both directions for a considerable period of time while this investigation continues.
“This is an absolute tragedy, and again I would ask the public and the media not to speculate as to the cause, as we continue to support the families of all of the victims.”