The three boys were celebrating their friend's 13th birthday

Josh Bartlett, Marshall Haynes and Liam Hastings, all 13, died while on a birthday outing when the Citroen they were in collided with a Honda.

Honda driver Howard Hillsdon, 21, from Yarnton, also died. Four boys and a woman remain in hospital.

Josh and Liam were pupils at Oxford Community School while Marshall went to Peers School.

Roadside checks

The crash, on 28 May, is thought to have happened when the Citroen Xsara, driven by the 45-year-old mother of one of the surviving boys, crossed the central reservation of the A4142 eastern bypass.

It is then thought to have collided with Mr Hillsdon's Honda.

Aiden Wood, Anton Dublin, Jake Proper and Conor Hunt were hurt

Three other cars were also involved.

Officers returned to the scene on the A4142 Oxford bypass on Saturday evening, to carry out roadside checks as part of their investigation into the cause.

The surviving boys, Conor Hunt, 12; Jake Proper, Aiden Wood and Anton Dublin, all 13; are all being treated at the John Radcliffe II Hospital in Oxford.

The 45-year-old woman driver is in a critical condition in the Great Western Hospital in Swindon.

The seven young friends were on an outing to celebrate the birthday of the woman's son.