View SSL/TLS certificate in Safari 5+ when no padlock icon shown

According to Apple , > With Safari 5 through 5.1.7, a lock icon appears near the top right > corner [only] if all of the webpage's content uses a secure connection. That's all very well, but normally to view the SSL/TLS certificate for a webpage serving content over HTTPS, one would click the padlock icon. Because the icon is not present on pages that serve only *some* of their content over SSL/TLS, there ought to be another way to view the certificate, but what is it?