Visible crew/equipment: In the episode "Head over Heels," twice you can see the cameras mounted on the walls that are used to film this series. The first one is during the cross-examination of Miss Morris and the second time is during the defence summing-up.
Factual error: Despite the several episodes containing serious offences like murder, you never see two barristers on any side. It is usual with serious offences for each party to have one Queen's Counsel and a junior, and although there are exceptions, we never ever see this very common practice in any episode.
Factual error: An error which arises from having the same characters in different episodes is that the frequently-featured barristers vary the cases they deal with to a laughable extent. One Queen's Counsel (A barrister appointed as counsel to the British crown) was seen defending a murderer in one episode and prosecuting a trivial offence in another. Someone of this seniority would not fluctuate workload like this.
Factual error: During an episode which concerned a sweet shop owner charged with touching a young girl, there were two instances where a question of law arose. The judge should have sent the jury out of the court to discuss this with the barristers, but he didn't and exposed the jury to biased information.
Factual error: There are several instances of barristers, judges and court officials wearing the wrong court attire. Ushers are seen in wigs, which they don't wear, the judges have their winter garments on, despite it being summer and vice versa. Similarly, none of the barristers are ever presented as "QCs" and yet several are wearing the QC silks, but none have the waistcoat which goes with it.
Factual error: At several points, barristers who are not QCs are seen leaning on little podiums or rostrums (which they have brought into the court themselves). Only QCs are allowed to use these.
Factual error: In one episode, I think it's the one entitled "Breaking Point" which featured an assault, right at the end the barristers from different sides are seen shaking hands in the courtroom. This is a breach of one of the most important rules of the British adversarial court system and it's second nature to barristers not to do it.