FATAL injuries sustained by toddler Leiland-James Corkill could not have been caused by an accident, a court has been told.

The 13-month-old boy died in hospital the day after sustaining 'devastating' brain injuries from an incident in Barrow.

Laura Castle, who hoped to adopt Leiland-James alongside husband Scott Castle, denies murdering the child but admits manslaughter.

Neuropathologist Dr Daniel Du Plessis told the jury at Preston Crown Court there was 'compelling' evidence Leiland-James's death was caused by a 'non-accidental' event.

Giving evidence, he told the court it was likely the 'devastating' injuries were caused by 'severe' force.

Asked if the kind of injuries the child suffered would usually alert doctors to a non-accidental cause, he said: "Absolutely."

He told the court Leiland-James, who was originally from Whitehaven, died because of a lack of oxygen and blood to the brain, which was found to be significantly swollen.   

One thing that could have caused this was a 'traumatic head injury', he said.

Dr Du Plessis said the injuries were consistent with repeated forward and backward motion that would have had an effect similar to whiplash.

On day four of the trial the jury was read transcripts of several of Laura Castle's police interviews.

Mrs Castle described how on the morning of January 6 she had given Leiland-James his breakfast and then sat with him on a sofa at their home.

Leiland-James was sat on her left thigh, she said, when she tried to get up.

She said the boy ended up falling forwards onto the floor, making contact with the ground in front of the sofa with his head.

She described hearing a 'bang' but told officers the only injuries she noticed when she picked him up were to his lip.

Mrs Castle said she then went upstairs to the bedroom to her husband Scott Castle, telling him: "Wake up. He's fallen."

They then called an ambulance, saying Leiland-James was struggling to breathe.

During the interview, an officer expressed concern about 'how difficult' the interview was for Mrs Castle.

But she said: "I'm fine. Please don't be kind.

"I don't deserve it.

"I'll never forgive myself. I'm not a bad person."

The court heard how during the interviews it was put to her that she initially told doctors at Furness General and Alder Hey hospitals and others that Leiland-James had fallen from the sofa while she was in another room.

Asked why she changed her story, Mrs Castle said she was 'frightened' to reveal what really happened because she 'would lose my whole life and my family'.

In another interview, she told police: "I'm sorry. I've lost my son through my error."

Mrs Castle denies child cruelty. Mr Castle denies causing or allowing Leiland-James's death. 

The trial continues.