The Old Bailey jury trying motorway killer Kenneth Noye has been sent to a hotel overnight to consider its verdict.
Noye, 52, from Sevenoaks, Kent, has denied murdering Stephen Cameron during a road rage incident on the M25 Swanley interchange on May 19, 1996.
Prosecution allege he stabbed the 21-year-old in anger "and maybe pride" when he found he was not winning in the fight.
Mr Cameron from Swanley, Kent, was stabbed in the heart and liver.
Before he sent the jury out, Lord Justice Latham told them that the core of the case was the question of self-defence.
"Might Mr Noye have been acting in self-defence when he used the knife?
"Or do you think when he got out the knife it was to confront Stephen Cameron or even up the odds so he did not leave the scene a beaten man?
"But even if you conclude he may have believed he needed to defend himself, you still have to consider the very important question of whether the use of the knife was really out of all proportion to the incident."
The judge warned the jury that the alternative verdict of manslaughter was "not there as some easy, simple way of coming to a compromise if there are different views among you.
"You can only bring in a verdict of manslaughter if you are genuinely satisfied there was unlawful violence but that there was not the requisite intent - or that he was provoked."
At 4:30pm the judge called the jury back into court and when he was told that the eight women and four men were not on the verge of making a decision he sent them to a hotel for the night.Reuse content