The Guardian reports that new research, which examined the rulings of Israeli judges presiding over parole hearings in criminal cases, showed that judges tend to be more lenient at the start of the day and immediately after a scheduled pause in court proceedings, such as lunch.

Jonathan Levav, an associate professor of business at Columbia University and co-author of the research paper, said: "You are anywhere between two and six times as likely to be released if you're one of the first three prisoners considered versus the last three prisoners considered."

The authors of the paper, which is published in the Proceedings of the National Academy of Science, examined over 1000 rulings made in 2009 by eight judges. They found that the chance of a more favourable ruling peaked early in the day and steadily declined from a probability of 65 per cent to almost zero. The probability then spiked back up to about 65 per cent after a meal break.

"What we're finding here is a basic psychological effect, and there's nothing different between the psychological effect on a British judge and an Israeli one," said Levav.

However, other variables also influenced a judge's ruling, such as the number of times a prisoner had been locked up previously and the option of a rehabilitation program. Other factors, such as the severity of the crime, time spent in prison, gender and ethnicity were found not to have a significant effect on the rulings.

The paper speculates that meal breaks may "replenish" mental resources by allowing the judge to rest, improve mood or increase glucose levels in the body.

"I don't measure the judge's mood. I don't measure the judge's glucose level. It's just a very consistent empirical regularity," said Levav.