I use Microsoft Outlook, which has a spam-reporting button.
It appears that when I report a lot of spam, VM email thinks that my computer is infected and sends me an email saying "You have received this email as one or more of your Virgin Media mailboxes has recently been locked due to suspicious activity being detected..."
The suspicious activity detector should have this email address whitelisted as a recipient:
because it is used for reporting spam and so does not indicate suspicious activity.
There are other phishing/spam-reporting email addresses that Microsoft publishes, perhaps those could be ignored too - I expect the VM email security team knows more of them than I do.
Are you forwarding on the spam messages? I had a similar issue (I use the email service linked to a personal domain name) when forwarding messages to the government phishing address, where my email provider was blocking the forwarded spam from leaving their servers. They advised that this was to do with them being concerned that their servers would be detected as being a source of spam by third party services and finding their servers blacklisted. Can't say I know how all the various detection, reporting and blacklisting processes work and whether this was a plausible explanation or not.
Somewhat ironic that facilities to report spam end up being blocked because they are receiving spam traffic. I only ever reported the worst and most unpleasant spam. I have now just given up doing so.
Hi Andrew, thank you for posting and bringing this to our attention!
Sorry to hear that this is happening and causing you issues. I have raised this internally with our IT departments, and Internet security team. I will return to this thread with an update as soon as possible - thank you for your patience in the meantime.
In the meantime, there are thorough instructions on how to fix the issue if your account has been locked for suspicious activity on this thread.