A woman accused of causing the death of a five-month-old baby was suffering from undiagnosed dementia, a court heard.

Cambridge Crown Court heard that Shelagh Robertson’s dementia was worsening during the pandemic when there were fewer opportunities for face-to-face contact.

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 serious injuries.

Robertson, of Stables Yard, Waterbeach, denies causing the infant’s death by careless driving and is now on trial.

Professor of cognitive behavioural neurology at the University of Exeter, Adam Zeman, was instructed by defence lawyers to compile a report on Robertson.

He told jurors that the defendant had “dementia caused most probably by Alzheimer’s disease in a slightly atypical presentation”.

Prof Zeman said Robertson would have been at “high risk of becoming confused at that junction and one possible outcome of the confusion would be to look the wrong way”.

He added that “some forms of dementia are diagnosed relatively late as the features are rather subtle".

“The time Robertson’s problems were getting more severe coincided with the pandemic so there would have been fewer opportunities for face-to-face contact than there normally would be," he added.

Expert witnesses added that Robertson had “few close relatives” and her husband was “severely unwell”, which was significant as “it’s often spouses who bring you along” to a dementia clinic.

Jurors were shown an MRI scan of the defendant’s brain, and Prof Zeman said it showed “shrinkage” of a part of the brain associated with memory and language.

He said that if he saw someone at his dementia clinic with the “difficulties” he saw in Robertson he would “advise them immediately not to drive”.

Former teacher Ms Brown, who said she has known Robertson since around 2010, told the court that she was last driven by the defendant in the winter of 2018.

She recalled the occasion when she was a passenger in Robertson’s car and said when Robertson approached a junction on the A10 she “seemed uncertain of how to proceed”.

“I began to feel unsafe and wondered if something was the matter,” she said.

James Leonard, defending, said Robertson will not be called to give evidence.

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