I once went to the Old Bailey as a tourist. An official stuck his head round the door of the public gallery and whispered: ‘Court number one – murder!’ The judge glared as the gallery emptied with the sound of galloping hooves. I sat tight even though a member of staff had stuck a notice on the door saying FRAUD = BORING. It was actually quite interesting with some flashy barristers.

After lunch I ventured into court number one. The man accused was watchful; the dead girl’s sister wept as she was cross-examined with the help of a motherly Polish translator. It was worthy of Dickens but I decided that a murder trial was not my public spectacle of choice.

Today’s Supreme Court hearing involves two murders but the procedural calm helps to alleviate tension. The usher has made sure that families with opposing interests are seated apart. A man next to me drops off for a while, snoring gently. This is not fair on counsel who are firing on all cylinders, with a lot of animated intervention from the bench. Tip to counsel: I wouldn’t refer to the bench constantly as ‘my lords’. At one point Lady Hale makes emphatic use of a stapler.

It’s a big day for spotters. This is the first time that the Supreme Court and the Judicial Committee of the Privy Council are sitting together. They are hearing two linked appeals, R v Jogee and Ruddock v The Queen (Jamaica), involving the controversial principle of joint enterprise (can someone who incites murder be guilty of it?). Echoing in my head are the words ‘Let him have it’ from the notorious trial of Derek Bentley (hanged then pardoned).

If a potential death penalty had been involved I wouldn’t be here, but I checked the case details on the court’s website beforehand. As an uninformed layman I’d been startled when I discovered that the JCPC hears appeals from jurisdictions which still carry out capital punishment – as does Jamaica – although the court would never sanction such a penalty.

Four Supreme Court justices are accompanied on the bench today by the Lord Chief Justice, marking the significance of these criminal appeals.

The Supreme Court flag is joined by the Jamaican flag. As a spotter myself I wonder what robe the court usher will be wearing – Supreme Court (dark blue) or JCPC (maroon)? It’s blue. And has the oval JCPC rug with the royal crest (Honi soit qui mal y pense) been moved to court 1 – the largest court, being used for today’s packed-out hearing – from court 3 where it lies in front of the bench, on top of the Supreme Court symbol woven into the carpet? The answer is no, because another JCPC case is being heard today in court 3. (The role of the JCPC is technically to advise the monarch, hence the crest. And the mysteries of the Privy Council are explained in a new book: By Royal Appointment: Tales from the Privy Council.)

A couple of lawyers next to me are intent on counsel’s performance. ‘Good point!’ whispers one, and I long for a running commentary in an earphone.

I’m normally near the front, floating on a lagoon of dark suits, but today I’m at the back, giving ground to the crowd. I’ve just got back from Venice and my head is full of hectic colour and Renaissance paintings of near-naked bodies, not appropriate for today’s sober outing.

This post originally featured on Isobel’s blog Drawing from an uncomfortable position on 29 October 2015.