As a courtroom drama, Silk has much to recommend it. Whatever practitioners may tell you, most court cases are pretty dull, so you need a strong plot and a cast of larger than life characters to inject the necessary drama.

Peter Moffatt, who scripted the series, has long form for this, including Kavanagh QC and North Square. He is himself a barrister and, even if he no longer practices, it enables him to maintain a healthy measure of authenticity.

But this is telly and the viewers (or the TV controllers who think they know what viewers want) expect thrills and spills and heartache. Whereas in the court procedure rules the overriding object is to attain justice, in television the overriding objective is to gain ratings. If authenticity has to take a back seat, so be it.

So how accurate a portayal of life at the Crim Bar is Silk? The central premise – ambitious young set of chambers, two mid-career candidates for promotion to Queen’s Counsel (known as “taking silk” because of the more fancy gown you get to wear), but only one can succeed – is a good one.

The frenetic business of chambers, effectively governed by the wily senior clerk, Billy Lamb (played by Neil Stuke), pulling strings and doing deal behind the scenes, is well captured. So too are such routine aspects of barristerial life as the last-minute handing out of briefs, the late night reading up of cases, the panicky rush to court and the mumbled apologies to clients you’ve only just met and whose liberty hangs in the balance of your competence (or lack of it).

Two of the four central characters are, however, flawed. Our heroine, Martha Costelloe (played by Maxine Peak), is a bleeding heart brief who spends too much emotional energy sympathising with (often undeserving) clients, and while this may not be uncommon at the Bar, it is rarely a quality that makes for success at the QC level. For that you need steely detachment and unwavering ambition. By contrast her rival, Clive Reader (played by Rupert Penry-Jones) — a first class shit whose ruthlessness is matched only by his arrogant good looks (so I’m told) — is absolutely spot-on in the authenticity department.

Also true to life is the female pupil, Niamh Cranitch (played by Natalie Dormer), who comes from a judicial family; and so too would be the female pupil who sleeps with her pupilmaster (no need to guess who he might be) — but not if they are one and the same person. (If your dad were a judge, you wouldn’t need or want to sleep with your pupilmaster.) Still, you can just about believe in Niamh, however naive. It’s with her fellow pupil (and rival for a tenancy in chambers), Nick Slade (played by Tom Hughes), that the taut wire of stretched authenticity finally snaps.

In what parallel forensic universe would a woolly-hatted ex-muso who doesn’t seem to know his Archbold from his elbow, let alone such hoary old chestnuts as that one about not shaking hands with another barrister (a rule only spotty pupils actually observe these days anyway), have ever beaten off the competition to gain a pupillage in a busy London set? This bumbling clown seems to have been included for no better reason than comic relief, and the preposterous way he carries on (shoplifting his wig and gown, for example) doesn’t help matters. With Moody Martha as his pupil mistress, it’s hard to see how he’s going to shape up in time to get taken on.

Notwithstanding these character flaws, the series remains compulsive viewing. Although the six parts follow an overarching storyline, each one-hour instalment contains a complete and self-contained case, and each case airs an issue of the sort that barristers constantly come up against. Should you lie for your client? How much should you disclose to your opponent, or the court? Should you be able to choose your client, or should your client choose you? What if you know your client is guilty? These are the sorts of questions you often get asked by civilians and it’s good to see them aired in a TV drama, alongside the more torrid plotlines about rivalries in love and office politics.

SILK continues Tuesday evenings 9pm BBC1 Also on BBC i-player.