Officers are appealing for witnesses and information after a serious collision occurred on the A505 Baldock bypass.

The incident happened on Friday (13 September) at around 10.50pm, on the northeast-bound carriageway, close to the junction with Deadmans Hill.

A black Ford Focus was travelling towards Baldock from Royston in lane two, when it collided with a white Mercedes E220, which appears to have been driving the wrong way up the same carriageway.

The female passenger of the Mercedes - a 56-year-old woman from Graveley - is currently in a critical condition in hospital. The driver, a 64-year-old man from Letchworth, suffered minor injuries.

The driver of the Focus, a 20-year-old man from Royston, suffered leg injuries and was taken to hospital.

Detective Sergeant Shona Birkby, from Hertfordshire Constabulary's serious collision investigation Unit, said: "We are appealing for witnesses who saw the collision or anyone who saw the Mercedes prior to it, to please contact us.

"If you were driving in the area with a dash cam, we would also like to hear from you."

Call the non-emergency number 101, quoting reference number 817 of 13 September.