Question: (Inspired by [Can a lawyer subject the court to a (temporary) ruse for a legitimate purpose?](https://law.stackexchange.com/questions/36934/can-a-lawyer-subject-the-court-to-a-temporary-ruse-for-a-legitimate-purpose))

Under which circumstances are witnesses asked to identify people present (in particular defendants) in the courtroom?

* In which jurisdictions is this a thing? (I know it happens in the US; what about the UK, etc?)
* Are there rules mandating it (either local court rules, statutes, or jurisprudence), or is it something the parties may choose to do or not? If the parties choose, why would they do or not do it?

Answer: 
[canada](/questions/tagged/canada "show questions tagged 'canada'")[criminal-law](/questions/tagged/criminal-law "show questions tagged 'criminal-law'")

In Canada, this is called "in-[dock](https://justice.org.uk/in-the-dock/)" identification and, while not prohibited, it is recognized to have very little probative value. It has "particular frailties over and above the normal frailties attaching to identification evidence" and "adds little" (*R. v. Izzard* (1990), [54 CCC (3d) 252](https://canlii.ca/t/gd876), pp. 255-56 (Ont C.A.); *R. v. F.A.* (2004), [183 CCC (3d) 518, para. 47](https://canlii.ca/t/1grgd#par47) (Ont. C.A.)).
**[england-and-wales](/questions/tagged/england-and-wales "show questions tagged 'england-and-wales'")**

In a similar vein to the other answers for Commonwealth jurisdictions, a *Dock Identification* is possible but rarely allowed in the Crown Court. That said, a magistrates' court may consider using it for expediency for summary trials.

The [Crown Prosecution Service](https://www.cps.gov.uk/legal-guidance/identification) offers this:

> 
> **Dock Identification**
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> This term refers to the identification of the accused for the first time during the course of the trial itself, by a witness who has not previously named him or identified him by means of a Code D procedure.
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> In view of the dangers posed by dock identification, the CPS and Attorney General’s Office have undertaken, in relation to offences on indictment, that:
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> *“The [prosecution] … will not invite a witness to identity, who has not previously identified the accused at an identity parade, to make a dock identification unless the witness's attendance at a parade was unnecessary or impracticable, or there are exceptional circumstances”*
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> As a result, **a judge will normally prohibit any such identification during a trial on indictment but different considerations may apply in minor summary offences.**
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>