The mother in her 40s was reportedly travelling with other family members when the accident happened.
A British woman is among three people who have died in a three-car collision on a motorway in northern France.
Emergency services were called on Sunday at around 6pm to a crash between two cars and a van on the A26 near Neuville-Saint-Vaast and Thelus.
More than 65 firefighters and nine ambulances attended the incident, which took place as roadworks were carried out in the Reims-Calais direction.
A statement from the French administrative region, Pas-de-Calais, said: “This accident took place between three vehicles: Two cars and a British nine-seater family vehicle.
“The assessments made indicate that 17 people were involved (including seven British nationals and eight minors). Three people are dead, five are in critical condition.”
Miriam Posen, from Stamford Hill, London, has been named in media reports as among those who have died.
The mother, aged in her 40s, was reportedly travelling with other family members when the accident happened.
A Foreign, Commonwealth and Development Office spokesperson said: “We are in contact with the local authorities following a road traffic accident in France and have offered our assistance to the family.”
Two of the people critically injured were transported by helicopter to hospitals in Lille and Arras, the Pas-de-Calais statement added.
A spokesperson for French prosecutors in Arras told the PA news agency that it is looking into the incident, and those involved will be interviewed when their health improves.
Jacques Billant, prefect of Pas-de-Calais – who represents the area, also thanked emergency services for their “responsiveness and professionalism in the management of this event and the assistance provided to the victims”.
Witnesses who attended the accident were also offered psychological care, according to the administrative region.