AS A juror, I know what I have to do. I must put aside preconceptions and look at the facts presented in court. I must consider all the evidence laid before me and decide, on the basis of this alone, whether the defendant is guilty or innocent. I can confer with my fellow jurors and perhaps ask the good-looking one for a date. But I must not allow anything I have read, watched or heard about OJ Simpson to influence me.

It will not be easy. Like half the developed world, I have long since OD'd on OJ. None the less, I shall try to overcome any prejudices felt towards or against the defendant. But what a strange coincidence. The media frenzy that began with Simpson's nationally televised freeway chase has now focused on the selection of the jury, and by a quirk of fate I have been summoned for jury service on Monday.

Unfortunately, I shall not be fulfilling my duty in California, where jurors are allowed to attend court in beachwear. Instead, I must report to the Crown Court of Knightsbridge. Or, rather, its annex in the historic but resolutely glamour-free district of Borough, south-east London.

The location itself presented the first real challenge to my sense of justice and fair play. When the jury service summons arrived a few weeks ago I completed it with a sense of begrudging obligation. How dare they ask me to cross a bridge, to travel south of the river] My friends felt the same way. When I told them which court I must report to, their response was unanimous. 'Guilty,' they said, without a moment's hesitation.

Well, it stood to reason. South- east London, full of crooks and wife-beaters, right? And then there was the loss of earnings. 'How much do they pay you?' asked my friends. 'Cab fare and lunch,' I replied. 'How long does it last?' they asked, once the shock had passed. 'Indefinitely,' I sobbed. 'Maybe it'll be a gangland murder, dismembered corpse,' they cooed.

So I lapsed back into my habitual moral torpor, where I might still abide, were it not for CNN and Larry King Live, 'the world's only global talk show'. It was beady-eyed, bifocaled Larry, he of the striped shirts and red braces, who pricked my conscience. Slumped by the television set, I was pondering ways to avoid my judicial duty when Larry popped The Big Question.

'How can this man get a fair trial?' he demanded of the experts. They chorused: 'It all comes down to the 12 good men and true, the ladies and gentlemen of the jury.' But not just any old jury. No, to ensure a fair trial for OJ, it seems, the jury itself must be tried first.

I watched, awestruck, as the experts explained how they would secure an 'appropriate' pool of jurors, from which a final selection would be made. 'It is crucial to select a jury with the right psychological and sociological profile,' said Lois Heaney, a 'trial consultant'. Her job was to draw up a profile of the perfect juror and then help lawyers to select candidates.

In Californian courts, both the prosecution and the defence have the opportunity to vet potential jurors. A similar right is granted to defendants in British courts, but is limited to appearance: if you do not like the look of a juror, you are allowed to swap him or her for another. In California, however, candidates can be asked to fill out questionnaires so that lawyers can ascertain their beliefs and values.

'A good question,' said Ms Heaney, 'is one that elicits a complex psychological response. Such as: 'What was the most significant informal 1earning experience of your life?'.'

Danny Davis, a criminal defence lawyer, was more prosaic. 'You've got to know what magazines and newspapers they read, particularly in this case.' It was crucial, he said, to specify the 'peremptories' that one should 'exercise' in the jury selection process. In other words, the criteria by which you would accept or reject a jury candidate. At the last count, the two legal teams had narrowed the field down to 250, from which they would select the dutiful dozen.

All this may well be necessary in the OJ Simpson case. In America many believe Simpson has already been found guilty once, by the media. In such a high-profile case, the motivation of all would-be jurors must be suspect. Despite the fact that they will receive only dollars 5 a day for the inconvenience, many would spill blood for the chance to pontificate in post-trial interviews and TV chat shows.

Things will be different down in Borough. No one will ask about my most significant informal learning experience or which magazines I read in order to determine my moral constitution. But, thanks to Larry's timely reminder, an overwhelming sense of responsibility now surges through me. Justice will be done. And if it is a gangland murder, who knows, maybe I will be invited to appear on Vanessa.