A lottery winner caused a fatal crash when he took his eyes off the road to find his young son's teddy bear, a court was told.
Matthew Topham, 31, who scooped a £45m EuroMillions jackpot in 2012, had reached into the back of his BMW to find the "upset" two year-old's toy.
Lincoln Crown Court heard he veered into another car's path, killing Mary Jane Regler, 75.
Mr Topham denies causing death by dangerous driving.
Jurors heard Mr Topham, who had been visiting his wife's family, took his eyes off the road "for up to three seconds" before the crash at North Cockerington, Lincolnshire, on 25 December 2019.
Prosecutor Michael Cranmer-Brown said it was "accepted that the collision was entirely the fault of this defendant".
"His attention was diverted from the road as he was looking behind him to retrieve his two-year-old son's teddy bear," he said.
He looked back into the footwell to try and find it, Mr Cranmer-Brown said, before returning his attention to the road.
Child's upset 'irrelevant'
Mr Topham, who had crossed into the opposite carriageway, later told officers at the crash scene he had attempted to take evasive action but "it was all to no avail".
Mrs Regler died from chest injuries while her husband Rodney was seriously injured.
The prosecutor said it was "significant" that Mr Topham told police during interviews that "it was out of character to do what he did."
Concluding his opening remarks, Mr Cranmer-Brown said the child's upset was "irrelevant" and Mr Topham "knew that it would not be safe driving along a road and not looking where he was going".
"He could not just plough on," he said.
Mr Topham of Swinderby, Lincolnshire, denies causing death by dangerous driving and causing serious injury by dangerous driving.
He has admitted causing death by careless driving.
The trial continues.