Parliamentary privilege is a legal mechanism employed within the legislative bodies of countries whose constitutions are based on the Westminster system. In other legislatures, a similar mechanism is known as parliamentary immunity.

In the United Kingdom, it allows members of the House of Lords and House of Commons to speak freely before those houses without fear of legal action on the grounds of libel. It also means while a member is within the grounds of the Palace of Westminster he/she cannot be arrested. A consequence of this privilege is that legislators in Westminster systems are forbidden from uttering certain words, such as "liar" (see unparliamentary language).

The rights and privileges of members are overseen by the powerful Committee on Standards and Privileges. If a member of the house is in breach of the rules then he/she can be suspended or even expelled from the House. Such past breaches have included giving false evidence before a committee of the House and the taking of bribes by members.

Similar rights apply in other Westminster system countries, such as Australia. Further, though the legislature of the USA was not modelled on Westminster, the US system of privilege is based on Westminster practice.

Parliamentary privilege is controversial because of its potential for abuse; a member can use privilege to make damaging allegations that would ordinarily be discouraged by defamation laws, without first determining whether those allegations have a strong foundation. In Australia, such abuses have earned Parliament the nickname of the "coward's castle" - a place from which a member can attack others, while enjoying immunity from such attacks.

Privileges of the UK House of Commons

The ancient and undoubted rights and privileges of the Commons are claimed by the Speaker at the beginning of each new Parliament:

1. Freedom of speech;
2. Freedom from arrest;
3. Access of the Commons to the Crown (via the Speaker); and
4. That the most favourable construction should be placed upon the deliberations of the Commons.

Privileges not so claimed:

1. Right of the House to regulate its own composition;
2. Right of the House to regulate its own internal proceedings (to take exclusive cognisance of matters within the house);
3. Right to punish members and “strangers” for breach of privilege and contempt;
4. Right of impeachment; and
5. Right to control finance and to initiate financial legislation (as against the Lords).

Leading cases

• Haxey's case
• Duncan Sandys case
• Charles Bradlaugh
• Archibald Maule Ramsay
• Neil Hamilton
• Bill Heffernan
• Executive privilege
• Zircon affair
• Strode's case

External links

• Australia's Parliamentary Privileges Act 1987