UPDATED WITH VIDEO: Woman critically injured in second Castle Lane collision in 24 hours

Her condition was described on Wednesday morning as "serious and unstable".

The collision at Bournemouth’s Cooper Dean roundabout led to several hours of tailbacks on Tuesday.

Paramedics and police were called to the roundabout at 3pm and the woman, in her 50s, was taken to the nearby Royal Bournemouth Hospital. She was later transferred to Southampton General Hospital.

The crash involved a Smart car being driven by a Ringwood woman who was believed to be uninjured.

It happened around half a mile from the spot where a pedestrian aged in her 70s was seriously hurt in another crash on Monday, which involved a Yellow Bus outside to the hospital in Deansleigh Road.

The crash happened at the crossing close to the start of the on-slip for joining the dual carriageway on the way to Ringwood.

The slip road was closed by Dorset Police and traffic quickly built up around the roundabout. It remained closed until around 6.50pm.

A police spokesman said both the women driver and the pedestrian were local.

She said: "Officers arrived on scene where an ambulance crew were treating a woman at the roadside.

"Road closures were put in place at the on slip heading towards Ringwood and the slip road from Castlepoint.

"A further road closure was implemented at Queens Park Avenue.

"The injured woman was taken to Royal Bournemouth Hospital for treatment, where she remains in a serious condition."

At the scene, Sgt Mark Scammell said police were investigating the cause of the crash and the woman’s family was contacted on Tuesday afternoon.

He said: “We received a call to a single vehicle road traffic collision with a female pedestrian.

“As a result of that collision the pedestrian sustained serious life threatening injuries .”

Desmond Waller, 77, waits next to the roundabout for his wife, who works at Royal Bournemouth Hospital. "You have to be very careful at that crossing," he said.