prosecution or perjury) or statements made in a session of the legislature by a member thereof (known as 'Parliamentary privilege' in Commonwealth countries). Qualified privilege: A more limited, or 'qualified', form of privilege may be available to journalists as a defence in circumstances where it is considered important that the facts be known in the public interest; an example would be public meetings, local government documents, and information relating to public bodies such as the police and fire departments. Another example would be that a professor – acting in good faith and honesty – may write an unsatisfactory letter of reference with unsatisfactory information. Mistake of fact: Statements made in a good faith and reasonable belief that they were true are generally treated the same as true statements; however, the court may inquire into the reasonableness of the belief. The degree of care expected will vary with the nature of the defendant: an ordinary person might safely rely on a single newspaper report, while the newspaper would be expected to carefully check multiple sources. Mere vulgar abuse: An insult that is not necessarily defamatory if it is not intended to be taken literally or believed, or likely to cause real damage to a reputation. Vituperative statements made in anger, such as calling someone "an arse" during a drunken argument, would likely be considered mere vulgar abuse and not defamatory. Fair comment: Statements made with an honest belief in their soundness on a matter of public interest (such as regarding official acts) are defendable against a defamation claim, even if such arguments are logically unsound; if a reasonable person could honestly entertain such an opinion, the statement is protected. Consent: In rare cases, a defendant can argue that the plaintiff consented to the dissemination of the statement. Innocent dissemination: A defendant is not liable if they had no actual knowledge of the defamatory statement or no reason to believe the statement was defamatory. Thus, a delivery service cannot be held liable for delivering a sealed defamatory letter. The defence can be defeated if the lack of knowledge was due to negligence. Incapability of further defamation: Historically, it was a defence at common law that the claimant's position in the community is so poor that defamation could not do further damage to the plaintiff. Such a claimant could be said to be "libel-proof", since in most jurisdictions, actual damage is an essential