Matthew GarrettFinal thread on English legal case procedures for the moment. This time it's on disclosure, which is approximately what's called discovery in the US. Like most things I've talked about, there's rules - this time it's CPR 31 (https://www.justice.gov.uk/courts/procedure-rules/civil/rules/part31). The goal of disclosure is to ensure both sides of a case have as full an understanding of the facts as possible. That means that any potentially relevant documents are supposed to be disclosed to the other side.
Note that this doesn't just include documents that you're going to rely on yourself! In the absence of specific instructions about what's being disclosed, standard disclosure requires that you disclose all documents that hurt your case or benefit the other side's case. You don't need to draw attention to the nature of the document, you simply need to describe it and be willing to provide it.
Obviously this can be (a) a lot of documents, and (b) involve a bunch of stuff being made available that you would really prefer not to share. So there are limits - you can use disclosed documents in trial, but if they didn't come up then CPR 31.22 says you can't use them in any other way. Basically, if you didn't think using a disclosed document was necessary for your case, you act as if you never saw it (unless you ask the court for permission to do so and they grant it)
Anyway, if you make reference to having received emails from people indicating their willingness to testify against someone, and then don't disclose those emails, then it's reasonable to conclude that either those emails didn't exist or you didn't fully disclose everything you were supposed to. Talking about the content of disclosed material that didn't come up at trial is also potentially going to have bad outcomes.
(Obviously, if you choose to publish everything you're disclosing, then you're not going to have much opportunity to complain if someone then refers to it)