A five-year-old was taken to hospital with serious head injuries and a suspected fractured skull after an accident on the M65 last night.
The 44-year-old male driver also suffered broken bones in the crash at around 9.15pm on Thursday.
It is believed that a Subaru Impreza car was travelling on the slip road at junction 6 of the M65, for Rishton and Blackburn, when a silver car overtook the vehicle.
The Subaru came off the nearside of the carriageway and collided with a tree.
Sergeant David Hogarth of the Road Policing Team said: “We are appealing for anyone who witnessed the incident to get in touch so that we can establish how this accident happened.
“We would also like to speak to the driver of the silver vehicle who may have important information that could help us form a better picture of how the Subaru has come to leave the carriageway and crash.”
Anyone with information should contact Lancashire Police on 101 quoting log number 1325 of Thursday, August 21st or Crimestoppers on 0800 555 111.