Virgin Media's broadband subscribers struggled to access file upload sites last week, it has emerged.
The broadband provider revealed it was first notified of the problems on Thursday evening (May 13th), when customers highlighted that sites like MegaUpload appeared to be blocked.
However, Virgin Media has claimed in a forum posting that any blocking was not deliberate.
Peter Rafferty, who works on the firm's Help and Support Forum Team, said: "Virgin Media did not block these sites and we are investigating the root cause.
"In the meantime we have implemented a workaround, and customers should be able to now access these sites again. We apologise for any inconvenience."
Virgin Media recently refreshed the offers on its broadband and home phone bundles.
New subscribers can now get access to the L broadband package and unlimited weekend UK landline calls for £5 a month for the first three months, while the deal then reverts to £12.50 a month.