A spam attack last week saw thousands of Virgin Media customers cut off from their email accounts for four days.
The spam affected the company that processes messages delivered through Virgin.net. According to Virgin, users trying to log-on last week were greeted by an error message as legitimate emails were held back last week so the spam could be removed.
Emails are now being delivered but accessing them via webmail may take longer to restore. Virgin is also keen to stress that no emails have been lost.
"Since late Tuesday evening, some customers on our Virgin Media DSL service may have been unable to access email or webmail. This was due to a suspected spam attack suffered by our email supplier which also affected a number of other ISPs. No customers on our cable service were affected," a spokesman told the BBC.