Police are appealing for witnesses to a serious injury road traffic collision in Amersham.
At around 6.45pm on Tuesday 5 November, a grey Toyota Corolla and a blue Citroen C1 were involved in a collision on the A416 Amersham Road between the junction of Chiltern Road and Moor Road.
The driver of the Citroen, a man in his seventies, sustained life threatening injuries to his chest and remains in hospital in a serious and critical condition.
Officers revisited the scene on Thursday afternoon (13/11) to carry out forensic collision investigation work.