A woman has sustained 'life threatening injuries’ after being involved in a collision with a lorry in Maidenhead.
It happened just after 1pm on the one way system near Grenfell Island.
The woman has been airlifted to John Radcliffe Hospital in Oxford after suffering severe pelvic injuries.
The driver of the lorry suffered no injuries and is being interviewed by police.
King Street is still closed to traffic heading north towards the town centre and is being diverted along Shoppenhangers Road.
Qualified first aiders at Sainsbury's supermarket have told how they rushed to help the woman.
Staff at the Kings Street store were among the first on the scene after hearing the woman scream.
Team leader and first aider David Crerar said: "We heard a scream and a screech and three of us just quickly dropped everything.
"We went straight over to the road, I was one of the first people to get to her.
"I instantly checked her airway was okay."
The 42-year-old has worked at the convenience store since it opened in February.
He added the woman, who he believed to be in her 30s, did not speak as he tried to keep her conscious.
"She started to deteriorate but then a police officer turned up and at that point I did a handover with him."
UPDATE: 16.55 The road has now been reopened.
Top Ten Articles
The Met Office has issued a yellow alert for Windsor and Maidenhead, Slough and Wokingham, warning that rain moving eastwards across the south of the country may turn to snow in some places.