Reverse display order in conversation view

Conversation view shows a thread by timestamp in descending order (newer messages above older messages).

When away from my computer for a couple of hours, or a couple of days, I will frequently see a number of correspondents weigh in on a discussion. When I go to catch up on the conversation, reading the messages in reverse order from how it happened is quite awkward.

Kindly add an option to sort a conversation in the order it happened in, so the end-user can read the conversation from top to bottom, so it reads naturally. Ideally it should start scrolled down to the first unread message if there are previously-read messages in the conversation.

To borrow from the age-old top-posting bugaboo:

A: Yes.
>Q: Are you sure?
> >A: Because it reverses the logical flow of conversation.
> >>Q: Why is top posting frowned upon?

My apologies if this is already possible and I'm just overlooking a bit of user interface. I looked, honest.