Google did not flag it as a bad one and it looks quite convincing only the from email is noreply@notifications-hmrcgov.uk rather than noreply@notifications.hmrc.gov.uk. Oh, and it came to some made up name at this domain. Apart from that, I was about to open the Microsoft Word document that was attached...
You have new notifications relating to Tax Notices (P6/P6T). Please download attached document and sign Tax Form. Please complete, sign and date the following form and fax a completed form to HMRC at your earliest convenience on 03000 543 889. Please do not reply to this e-mail