Go on, give us the short version, because I know a lot of listeners will have that case lurking in the back of their minds as the reason they worry about this.

So in Three Rivers No. 5, the Court of Appeal held that only those within a corporate entity who are authorised to instruct the lawyer and authorised to seek and receive legal advice are to be treated as the client for privileged purposes.

So it draws what can be a fairly narrow circle around those who count as the client.

I'd also mention that the SRA's guidance on legal professional privilege when working in-house picks this point up.

But back to Abba, disclosure of documents was being given in the course of litigation and Glencore, the defendant... withheld from its disclosure certain documents passing between members of its client group, as understood under Fee Rivers No. 5, even when no lawyer featured in the communication.

And Abba argued that Glencore should disclose all documents which were communications between members of a client group unless those documents evidenced the substance of privileged communications or were intended to be sent to a lawyer but never were.

But I suspect you're about to add some important caveats because privilege is never quite as simple as we'd all like.

Well, there's no doubt that privilege can be tricky in practice.