Deleting mail from server with pop3

[Paul Moore <gustav@morpheus.demon.co.uk>]

If I understand the code correctly (*not* a foregone conclusion :-))
gnus uses pop3.el from the xemacs mail-lib package to do POP3
retrieval of mail. The sequence of events when retrieving mail is:
first, retrieve messages 1..N, then delete messages N..1.

I have a problem with this. My ISP has a tendency towards randomly
dropping the connection. When this happens during a mail retrieval, I
get a load of downloaded messages which haven't been deleted off the
server. This has two consequences - first, there is a big chunk of
data which gets downloaded twice, and second, mail gets duplicated (if
I let the crashbox be processed) or lost (if I delete the crashbox).

What I would prefer would be to delete each message immediately after
it has been downloaded. I looked at the code in pop3.el, and there
doesn't seem to be a way to achieve this as the code stands. And my
elisp skills are definitely not up to something like this...

Does anyone know of a way of achieving something like this? Or
alternatively, am I doing something wrong? If the connection drops
while pop3 is downloading or deleting messages, is there a way of
recovering *without* getting duplicate messages?

Thanks,
Paul (Just finished trawling through a couple of hundreds of spam
messages, each duplicated 3 times :-()

PS "Get a new ISP" is a reasonable suggestion, but unfortunately not
practical...