Beyond reasonable doubt

The defendants, Kailey Nightingale and Alindon Campbell, were both 20. Nightingale was accused of raping a 14-year-old girl; Campbell accused of the sexual assault of the same girl and her 15-year-old friend. Both the defendants and the alleged victims were black. One of the men was leaning on the glass, eyeballing jurors as they walked past on the first day. In his intense stare you could read either the crazed look of a rapist or the scared look of someone who is trapped and frightened.

The jury was a real mix: six men, six women, ranging from their early 20s to late 60s. One of the jurors was Asian and three were black. Most on my jury were professionals.

On the first day, we sat there with a stash of paper and pencils, and we were thrown into it. The prosecution told us a story. In August last year, two girls from the north were holidaying with family in south London. They went to the park, where they met Nightingale and, later, Campbell. Nightingale and the 14-year-old exchanged texts. When asked how old she was, the 14-year-old told Nightingale she was 16. When asked why in court, she said boys don't take you seriously otherwise. That was played up by the defence.

Later the same day they met up again and while the 15-year-old went to get a drink with Campbell, Nightingale and the younger girl walked into the stairwell of a block of flats where they began kissing. The girl told the court she had not consented to sex and while she did not say "no" at first, she had struggled to keep her trousers and pants up as he had pulled them down, a sign it wasn't consensual. But Nightingale insisted it was consensual; he even claimed to have left the stairwell to get a condom, which both agreed he used. She had cuts, but they could have been caused by normal sex.

When she said she was hurting, Nightingale stopped, withdrew, saw blood and went off to get some tissues. Meanwhile, the 15-year-old alleged that Campbell had sexually assaulted her. Right at the start we were told that Campbell had previous convictions for rape and sexual assault. When Nightingale disappeared, Campbell entered the stairwell where the 14-year-old said he demanded sex and threatened to strangle her if she refused. She objected, but he made her masturbate him. Cross-examined, he claimed they just chatted but he couldn't remember anything they talked about. Campbell denied he'd ejaculated, but a forensic scientist gave evidence that his semen DNA was present on a tissue the girl used to wipe her hands.

This was a pretty dark slice of city life that I don't normally encounter. Morally, what had happened that day in August was repugnant, but we had to try and focus on the evidence. You get over the discomfort of sitting there with a map of someone's genitals in front of you with marks drawn all over it quickly enough, but the worst moment is when both sides of the argument are presented and you realise what a difficult judgment you are faced with. I had some pretty bad nights' sleep later on.

The prosecution case ended too suddenly. It felt as if a lot of evidence was ruled out and important witnesses were never called. You are gathering pieces of a puzzle in your mind, and hope over time to find all the missing pieces. When they don't appear you have to form a judgment about the entire picture with two thirds of the pieces missing. That's very difficult.

I expected the police evidence to be the most precise part of the prosecution but this wasn't the case at all. A lot of the defence's cross examination of the police was about the exact time that the rape allegation had been made. The police were called quite quickly after the 14-year-old returned home and, it seemed, initially told relatives she had been "hurt". She was interviewed first by a WPC but she was never called as a witness. Instead, the officer who interviewed the 15-year-old girl gave evidence. He seemed very young and apologised to the judge for not wearing his tunic. Who cares what you are wearing? His contemporaneous notes were incomplete and he was unable to pinpoint when the rape complaint was made, which was critical. The defence suggested that "hurt" had been translated into "rape" by her grandmother in the heat of the moment.

The police also lost the 14-year-old's mobile phone at the police station. The men and girls had exchanged texts and calls, and we were told the elder girl tried to call the younger one when she was in the stairwell with Nightingale, but no mobile phone records were presented as evidence. Why? The detective in the witness box suggested this was for economic reasons, which also explained why police did not do a DNA test of the condom they found. It was never clear whether the condom they found was the condom that was used.

When so many things are not certain, it is incredibly difficult to make a precise judgment beyond reasonable doubt. You are dealing with such subjective matters - one person's word against another - and just the smallest detail would help fix something in time and allow you to make a concrete decision. It was really shocking that it was considered not financially viable to gather certain evidence. Who sits and makes those calls when it's a rape investigation?

Like most rape cases, this one ultimately came down to who you believed. The girls gave evidence via a video screen throughout. I don't think it helped. The men were in front of you, giving evidence in person. You were able to take a view on them. The girls were on TV, one step removed, something you could keep at arm's length. When it is so much one person's word against another, it is difficult if you have a virtual person at one end.

I felt the female prosecution barrister was less forceful than the male defence counsel. Judge Aidan Marron gave a concise summing up. It made it clear the prosecution had been quite even-handed, which I'm not sure you can be when presenting one side of an argument.

We deliberated for a day and a half. Under our laws, I'm not allowed to discuss the particulars of the deliberations of the jury but, generally, people bring their own life experiences and prejudices to bear on any case. But everyone approached it very seriously and honestly. There were no domineering characters; there was no talking over each other; and everyone got a chance to speak and ask questions. For a group of strangers, it was impressive how everyone made everyone else feel at ease.

We found Campbell guilty of sexual assault on the 14-year-old but we couldn't come to a decision on his alleged sexual assault of the 15-year-old. It was upsetting to realise just what a serious thing it is to send someone to prison. When the verdict was given, you could see him take another punch. I felt quite sorry for him at the end. You could only hope he'll get help. Last month he was sentenced to two-and-a-half years in prison.

Judge Marron told him: "You've shown not a morsel of remorse." We found Nightingale not guilty of rape. I looked at him as the decision was read out by the foreman and he briefly closed his eyes in relief. He didn't have the look of someone who had got away with something.