The judge in the trial of a pensioner accused of causing the death by careless driving of a baby boy has indicated he will send jurors out to start their deliberations on Thursday.

Shelagh Robertson, 75, was driving home from a shopping trip to Tesco when she turned into the path of an oncoming van on the A10 at Waterbeach in Cambridgeshire on January 22 last year, Cambridge Crown Court heard.

The van collided with Robertson’s car, forcing the van onto the pavement where it hit Rachael Thorold and her five-month-old son Louis Thorold, killing Louis and throwing Mrs Thorold into the air, causing her serious injuries.

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)

Robertson, of Stables Yard, Waterbeach, denies causing the infant’s death by careless driving, with her defence team arguing that she is not guilty by reason of insanity as she had undiagnosed dementia at the time.

James Leonard, defending, said in his closing speech that it was “obvious” Robertson’s driving “fell below the standard of a reasonable and competent driver”.

But he said that Robertson was “ill-equipped to negotiate” the junction due to her dementia, and she was unaware of this as she was undiagnosed at the time.

“She’s trying to be safe but she just doesn’t have the presence of mind to be safe,” Mr Leonard said.

Prosecutor David Matthew said in his closing speech: “There’s no doubt here that Shelagh Robertson is suffering from a form of dementia and was suffering from it in January 2021.”

He said that an MRI scan of Robertson’s brain which showed shrinkage of a part of the brain associated with memory and language, taken in September or October of last year, is “strong evidence of that”.

But he raised the question of “where on the slope of dementia Shelagh Robertson was in January 2021”.

“It’s not just a question of whether someone has dementia, it’s a question of how bad is it,” he said.

Mr Matthew said Robertson has no previous convictions.

The judge, Mark Bishop, told jurors that to return a special verdict of not guilty by reason of insanity they must be satisfied, on the balance of probabilities, Robertson had dementia at the time and either did not know what she was doing or did not know that what she was doing was wrong.

He said that this “doesn’t include a momentary failure to concentrate”.

Adam Zeman, professor of cognitive of behavioural neurology at the University of Exeter, 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”.

The trial continues.