The group of boys were celebrating their friend's 13th birthday

They were in a Citroen Xsara when it crossed the central reservation of the A4142 near Oxford and hit another car.

The driver of the other car was killed along with three of the eight Xsara passengers, all 13-year-old boys celebrating a friend's birthday.

The woman Xsara driver, 45, is critical after an operation, while two of the four surviving boys are also critical.

The woman is being treated in the Great Western Hospital in Swindon, while the four boys are at the John Radcliffe II Hospital in Oxford.

Howard Hillsdon was described by his family as "outgoing"

Her son was celebrating his birthday with his friends when police say the woman appeared to have lost control of her car.

He is among those being treated for non-life-threatening injuries at the John Radcliffe.

After crossing the central reservation, the Xsara collided with an oncoming car, leading to pile-up involving several vehicles.

Howard Hillsdon, 21, driving the other car, was killed, while three of the woman's seven passengers, also died: Josh Bartlett, Marshall Haynes and Liam Hastings, all aged 13.

Police are continuing their investigations into the cause of the crash and council safety officers have launched an inquiry into whether there should have been a central barrier on the stretch of road.