Spanish Formula One driver Maria De Villota was fighting for her life on Tuesday after suffering serious injuries during a crash in testing for the Marussia team, it was confirmed.
A spokesman for the East of England Ambulance Service said De Villota had sustained "life-threatening injuries" in the early morning crash at Duxford Airfield in Cambridgeshire.
Marussia confirmed in a statement that the 32-year-old test driver from Madrid had been transferred to hospital after her car collided with a support vehicle during a test lap.
"At approximately 9.15am (0815 GMT) 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," Marussia said.
"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."
BBC radio presenter Chris Mann, who witnessed the crash, said De Villota's car had ploughed into the truck after suddenly accelerating.
"She got into the car, fired it up and did a test run at probably about 200mph in the rain," Mann said.
"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."
De Villota, the daughter of former Spanish Formula One driver Emilio De Villota, was given a test drive by Renault last year and has previously raced in Spanish Formula Three and the Daytona 24 Hours.
Women drivers remain a rarity in Formula One.
In April this year Williams signed German touring car driver Susie Wolff as the team's development driver.
The last woman to enter the F1 world championship was Italian Giovanna Amati, who failed to qualify for three races at the start of the 1992 season with Brabham.
Five women have entered F1 races in the past, the most prolific being Italian Lella Lombardi, who started 12 grands prix in the 1970s.
Marussia began racing in 2010 under the Virgin banner. The team rebranded as Marussia in 2012, with Charles Pic driving alongside Timo Glock.
The team has struggled to make any impression on the championship however, failing to score any points this season.