The logical thing to do with phishing emails is to forward the whole thing to yourselves, I've just spent over 25 minutes trying to find such an address. All I can find is reams of stuff not truly related to phishing, but to security in general, even a search engine address 'Phishing email... how to report? - Virgin Media Community' is useless, no direct answer.
Make you wonder if Virgin are actually bothered about phishing.
For phishes targetting other companies you use and love to support, emailing out phishes would normally be rejected by the outbound spam filter. In that case you'd need to click three bar button then view source, copy the source and send the phishing email code on to the company you want to report it to via one of your other email addresses (Non-VM one.)
Edit: Added a bit at the end
- - - - - - Any opinions expressed by myself are entirely my own and do not represent Virgin Media in any way.