So a witness can only appear via Zoom due to being in another country (or refuses to come to the country where the trial is being held).
They are found in contempt of court for whatever reason.
How would the punishment (in the UK up to 2 years in prison) be enforced?
Interested in any jurisdiction not just the UK.
A warrant for the arrest of the person on contempt charges could be issued although this probably wouldn't be a valid basis for extradition and instead would only be enforced if that person came to a place where the court has territorial jurisdiction.
The person held in contempt could be fined, with the fine reduced to a money judgment, and the judgment could be enforced against any assets or income of the person held in contempt that are, or are in the future, within the jurisdiction of the court. The money judgment could also be domesticated to a jurisdiction where the witness has assets to enforce the judgment through the local courts there.
If the witness is a party to the case, or is in some close relationship with a party to the case such that the party ought to be able to exert some control or influence of the witness, sanctions related to the case itself could be imposed.
The testimony of the witness could be disregarded as a sanction if appropriate.
If the witness were testifying involuntarily pursuant to letters rogatory (which is basically a subpoena from a jurisdiction where the witness is not located that is domesticated in the jurisdiction where the witness is located by a local court in accordance with local law), the court issuing the letter rogatory could sanction the witness according to domestic law for contempt of court for violating the commands issued in connection with the letters rogatory.
A simple declaration that a person was in contempt of court could sometimes have collateral consequences for that person, for example, in loan applications or background checks or violating the term of some contract that was the basis of the obligation of the witness to testify, or in connection with a plea agreement that called for that person's testimony (possibly in anther jurisdiction).
Courts have some discretion to fashion custom remedies in unique situations in response to someone's contempt of court.
