SpamCop allows you to receive messages with attachments of almost any size.
These can be downloaded via POP3 or accessed via IMAP.
But if you try to forward a message that contains attachments over the Maximum Attachment Size: 2,097,152 bytes you will probably run into problems and may be unable to forwarded it
IE 6.0 results in the error message: The page cannot be displayed. when clicking of the forward button.

Note: This limitation does not apply if forwarding of messages is enabled on your account; it only affects messages that are already in your inbox (or other folder) that you want to forward using the WebMail application.