A woman accused of causing the death of a five-month-old baby will say she had undiagnosed Alzheimer's disease at the time of the crash, a court heard.

Shelagh Robertson, 75, was driving home from a shopping trip on January 22 last year when she turned into the path of an oncoming van on the A10 at Waterbeach forcing it onto the pavement.

The van hit Rachael Thorold and baby Louis, who was being pushed in a pram by her, killing Louis and throwing Rachael into the air, causing her serious injuries.

Robertson, of Stables Yard, Waterbeach, denies causing the infant’s death by careless driving and is now on trial where she will say she had undiagnosed Alzheimer's, Cambridge Crown Court heard.

Ely Standard: Rachael Thorold with her son Louis, who was killed when a van mounted a pavement on the A10 in Waterbeach on January 22, 2021Rachael Thorold with her son Louis, who was killed when a van mounted a pavement on the A10 in Waterbeach on January 22, 2021 (Image: Credit: Thorold Family/PA Media PA Media)

James Leonard, for Robertson, told jurors: “The defence case is that Robertson had undiagnosed atypical Alzheimer’s disease both before the accident and on the day, and that’s what will lead to the conclusion that the defence of insanity is made out.”

Robertson sat beside her solicitor and family members in the well of the court today (Monday), listening to proceedings through a hearing loop.

The parents of baby Louis, Chris and Rachael Thorold, sat in the public gallery, and had placed a white soft toy elephant on a wooden ledge looking out over the courtroom.

Since Louis’ death, the couple successfully campaigned for a speed limit reduction from near the Denny End junction to near the slip road off Ely Road, Milton from 50mph to 40mph.

The couple also set up The Louis Thorold Foundation following their son’s death to campaign to reduce infant pedestrian road deaths in the United Kingdom to zero.

Rachael also used the website to blog about her recovery since the crash.

Ely Standard: Shelagh Robertson, 75, from Waterbeach, arrives at Cambridge Magistrates' Court.Shelagh Robertson, 75, from Waterbeach, arrives at Cambridge Magistrates' Court. (Image: PA Wire/PA Images)

Judge Mark Bishop told the jury that for a defence of insanity to succeed, they must be persuaded Robertson was suffering from atypical Alzheimer’s disease at the time of the crash.

David Matthew, prosecuting, said Robertson had turned right, driving her Mazda 2 car into the path of an oncoming Renault van that was travelling south along the A10 at the junction with Car Dyke Road.

“The impact forced the van on to the pavement,” he said.

“The van went over Rachael Thorold and her five-month-old son Louis.

“Louis was pronounced dead on arrival at hospital.”

The van was driven by delivery driver Andrew Freestone and Mr Matthew said Mr Freestone “tried to steer to his right” to avoid a collision.

The trial, due to last less than a week, continues.