A jury has been told to cast its prejudices and sympathies aside by a judge summing up in the trial of a man accused of the "road rage" murder of a retired solicitor.

Judge Mr Justice Singh said jurors must reach their verdict on whether Matthew Daley, 35, murdered 79-year-old Donald Lock "dispassionately and fairly".

Mr Lock was knifed 39 times after crashing at about 16mph into the back of Daley's Ford Fusion car on the A24 at Findon, near Worthing, West Sussex, just after 8.30pm last July 16.

The minor crash happened after great-grandfather Mr Lock, who was returning from a cycling meeting, was forced to brake suddenly after Daley made an emergency stop.

As Daley lashed out with a four-and-a-half inch knife, a witness heard Mr Lock yell "Help, help, get off me."

Another witness told the trial that Daley, who is being held in Hellingly medium-secure unit in East Sussex, looked "expressionless" during the attack, like he was "having a passport photo" taken.

Brighton and Hove Albion season ticket holder Mr Lock, who had recently been given the all-clear from prostate cancer, died at the scene as Daley sped off.

Jurors have heard that Daley had been suffering from mental health problems for 10 years, and his family had "pleaded" with mental health experts to section him.

Summing up, Mr Justice Singh told jurors: "You must reach your verdict simply on the evidence, dispassionately and fairly."

He added that jurors should not assume Daley is guilty because he opted not to give evidence in his defence.

The trial, at Lewes Crown Court, was adjourned to 10am on Friday.