Subject: Undelivered Mail Returned to Sender
From: [email-masked] (Mail Delivery System)
To: [email-masked]
Date: Mon, 9 Aug 2010 10:44:04 +0100 (BST)

This is the mail system at host server4.example.co.uk.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to <postmaster>

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

                   The mail system

<[email-masked]>: host mail.b.c[213.167.71.35] said:
    550 "Sorry, your message has triggered a SPAM block, please contact the
    postmaster" (in reply to end of DATA command)

Subject: foo
From: Fred Bloggs <[email-masked]>
To: John Smith <[email-masked]>
Date: Mon, 9 Aug 2010 10:44:03 +0100

hello