Qualified privilege is the third defence against libel following on from justification and fair comment. It can be used as a defence if it is considered that the information should be published in public interest.
Qualified privilege can be divided into two categories; Statutory and Common Law.
Statutory qualified privilege predominantly covers reporting in court and Parliament. A defamatory statement can be reported by a journalist without fear of being sued for libel. Of course, the report must be fair and accurate and free of malice, otherwise the defence for QP is lost. Statutory QP also covers public meetings, council meetings and police statements.
Common law QP is where privilege is applicable in certain circumstances. The example that McNae's Essential Law for Journalists gives is that of asking for an employment reference. The former employer cannot be sued for libel for what they say, even if untrue, as long as it was not motivated by malice. Common law QP is usually worked on by a case by case basis.
Another defence worth looking into is the Reynolds Defence. It is a ten point test which courts must take into consideration if a newspaper or journalist wishes to use QP as a defence against libel. The Guardian online published a highly informative article regarding The Reynolds Defence which may be of interest.
Details of the ten point test can be found on University of Winchester Media Law lecture notes, the link can be found below.