Marussia test driver Maria De Villota has been taken to hospital with "life-threatening injuries" after suffering an accident in Cambridgeshire this morning.
The 32-year-old Spaniard was taking part in her first test for the Formula One team at Duxford Airfield when she crashed into a support truck after completing her opening installation lap.
After treatment by trackside paramedics, De Villota was taken to the local Addenbrooke's Hospital.
In a statement, ambulance service spokesman Gary Sanderson said: "A woman has sustained life-threatening injuries and, following treatment at the scene by paramedics, she has been taken to Addenbrooke's Hospital for further care."
A Marussia team statement read: "At approximately 09.15hrs BST this morning, the Marussia F1 Team's Test Driver Maria De Villota had an accident in the team's MR-01 race car at Duxford Airfield where she was testing the car for the first time.
"The accident happened at the end of her first installation run and involved an impact with the team's support truck.
"Maria has been transferred to hospital. Once her medical condition has been assessed a further statement will be issued."
Cambridgeshire Police earlier confirmed they had been called to the airfield, home of the Duxford Imperial War Museum, at 9.26am.
Chris Mann, Drivetime presenter on BBC Radio Cambridgeshire, witnessed the accident.
He said: "She got into the car, fired it up and did a test run at probably about 200mph in the rain.
"The car was slightly misfiring but there didn't seem to be any concerns.
"She came back into the area we were in with the engineers. She slowed down but then suddenly, inexplicably accelerated through the crowd and smashed into the side of the truck.
"The top of her car and her helmet seemed to take the brunt of it.
"She didn't move for about 15 minutes.
"Fire crews were there within seconds and the ambulance within minutes.
"After a while we thought we saw some movement of her hands but she appeared to be unconscious or unable to move for quite some time."
The crash happened at the start of two days of testing at the site ahead of this weekend's British Grand Prix at Silverstone.
This year is the first season the team has competed as Marussia after the Russian sports car manufacturer bought a controlling stake in the former Virgin team.
Timo Glock and Charles Pic are the regular drivers for the team, which has yet to score any points this season.
De Villota is the daughter of retired Formula One driver Emilio de Villota.