A mother who smoked cannabis before crashing off a motorway, killing her daughter and another teenage passenger, has been found guilty of causing death by careless driving.

Former youth worker Anastasia James, 37, was convicted by a jury of causing the deaths of Destiny James-Keeling and Megan Marchant while unfit through drug use.

Destiny, 14, and 18-year-old Megan, died of head and abdominal injuries after James' Vauxhall Astra convertible plunged down an embankment and struck a tree beside the northbound M1 in January 2014.

A blood test taken around six hours later showed that James, a former good parenting co-ordinator, had smoked cannabis shortly before the smash near Shawell, Leicestershire.

Forensic examination of the scene also established that James - who claimed a defect on her car had made driving it like "being in a tunnel" - made no attempt to brake.

In a statement issued after James was convicted at Leicester Crown Court, Detective Sergeant Mark Partridge, of the East Midlands Serious Collision Investigation Unit, said: "James' actions that fateful day resulted in the deaths of two teenage girls, one of which was her daughter.

"This case shows the shocking effects of driving whilst under the influence of drugs.

"The deaths and now the subsequent conviction has devastated the families of all those involved."

James, of Thornton Close, Braunstone, Leicester, will be sentenced next month.