The concept of parliamentary privilege is often misunderstood to mean that politicians acquire personal privileges simply by being elected to Parliament. In fact, parliamentary privilege applies to Parliament as a whole rather than the individual members. It enables the House of Representatives, as the democratically elected House of the people, to go about its business, such as lawmaking, without interference from outside.
Developed over centuries of Westminster-style democracy in Britain, parliamentary privilege provides certain exemptions from general law which are considered essential for parliamentary supremacy over the Crown. These include freedom of speech, the power to obtain evidence, and the right for the House to control its own proceedings free from outside interference.
These privileges were hard won in times past, when elected representatives could suffer severe consequences for what they said in the House or be prevented from attending the House. For instance, in 1642 King Charles I entered the House of Commons in an attempt to arrest five members on treason charges for their part in opposing him.
The removal of those privileges, even today, could result in Parliament being prevented from carrying out its functions on behalf of those it represents.
This complex and often misunderstood subject is explained in the Parliament Brief: Parliamentary privilege, which can be accessed via the related link on this page.