The £45 million Euromillions winner is alleged to have been driving dangerously when he caused a fatal crash moments after setting off from his in-laws’ home near Louth after visiting on Christmas Day 2019.
Topham, 31, of Swinderby, has admitted he is responsible for the collision but says his driving was careless rather than dangerous.
He said he took his eyes off the road for “a split second” to retrieve a teddy bear which had been dropped in the rear passenger footwell by his two-year-old son.
Then, after finding the teddy and giving it back to his son, he looked up to see the headlights of an oncoming car.
Topham had drifted onto the wrong side of the road and was entering a right-hand bend. His BMW car collided head-on with Ford Fiesta.
As a result, Mary Jane Regler, 75, a passenger in the Fiesta, died and her husband Rodney, 77, who was driving, was seriously injured.
The couple were returning home after having Christmas Dinner with their son.
Today, prosecuting barrister Michael Cranmer-Brown told the jury at Lincoln Crown Court that by taking his eyes off the road Topham’s driving fell far below the standard of a careful and competent driver and was dangerous.
Mr Cranmer-Brown said: “The cause of the collision was entirely Mr Topham’s poor driving. He strayed into the opposite carriageway. He didn’t realise that was happening. He only realised when it was far too late for him or Mr Regler to be able to do anything about it.”
Paul Greaney QC, for Topham, in his closing speech to the jury said: “We say that the evidence establishes beyond doubt that Matt Topham looked away for a very short period and certainly a period of less than three seconds.
“Matt Topham was sober, he was well within the speed limit and he was driving a roadworthy vehicle. He was not on his phone, he was not driving aggressively or seeking to overtake. He made a single tragic error of judgement. What he did was careless but was short of dangerous driving.”
Judge Catarina Sjolin Knight has started her summing up to the jury, and is expected to ask them to retire to consider their verdicts this afternoon.
Topham denies causing the death of Mary Regler by dangerous driving but has admitted the lesser charge of causing her death by careless driving.
Topham also denies causing serious injury to Rodney Regler by dangerous driving.
The charges follow the head-on collision on Louth Road, North Cockerington, near Louth shortly before 6pm on Christmas Day 2019.
The hearing continues.