Police would like to speak to the driver of a silver Ford Focus who is thought to have been involved in the build-up to the collision.
It is believed that shortly after approaching at speed from behind and flashing their lights, the driver of the Ford Focus overtook and pulled in front of the Polo in the second lane, causing the driver to break harshly.
When the Polo later went passed the Ford Focus - which was in the first lane - at the exit slip road to the services, the Focus steered right and caused the Polo driver to break suddenly again, leading to the collision with the Mercedes tanker.
The Focus left the scene and was last seen leaving junction 26 and driving up the M606.
The 51-year-old Bradford woman, who was a passenger in the front seat of
the Polo, is in hospital in a serious but stable condition.Anyone who has witnessed any part of this incident or who believes they saw this Ford Focus and can provide any further detail about the vehicle to make contact with the Western Area Safer Roads Unit on 101 with information.
