At about 650pm on Saturday (December 17) a collision occurred between a grey Honda HR-V and a black Mercedes A Class on the A505 from Royston to Baldock at the junction of Deadman's Hill. 

The passenger of the Honda suffered serious injuries and was taken to Addenbrooke's Hospital for treatment. 

The drivers both suffer minor injuries. 

Sergeant Tim Davies from the Bedfordshire, Cambridgeshire and Hertfordshire Road Policing Unit is investigating. He said: "I would like to appeal to anyone who was in the area at the time and who saw the collision or who has any dashcam footage which may assist our investigation to please contact me." 

You can report information online at herts.police.uk/report, speak to an operator in our Force Communications Room via our online web chat at herts.police.uk/contact or call the non-emergency number 101, quoting ISR 684 of 17 December.