“Parliamentary privilege” exists to allow MPs to ask questions, put forward views, criticise, challenge and propose, without fear of interference from outside the House, such as, for example, a lawsuit for slander. What privilege gives is immunity in respect of what MPs say, though there is a limit: their constituents can throw them out at the following election if they say particularly stupid or repulsive things, or things opposite to what, at the previous election, they offered to say if elected.
Does parliamentary privilege protect them against lying? There have been egregious examples of untruths told to parliament in recent times—the reasons given for invading Iraq are a major case in point—and the troubling question about them is whether they were not merely untruths but actually lies. For a lie is a deliberate, conscious untruth, the intention of which is to mislead and manipulate; and in the case of the highest court in the land, the court of parliament, deliberate and intentional misleading of fellow legislators and the public at large is a profoundly serious matter.
For this reason it is an open and shut case that it is wrong to lie in parliament. The question before us is, however, a different one: should it be illegal to lie in parliament? Should MPs be arrested and charged when suspected of lying, should they suffer imprisonment and expulsion from the House of Commons if convicted? There is a good case for thinking so, given that the harm done by lies in parliament is potentially so great.
Considering this question requires considering the place of lies in the social economy of life. We all know that lies can keep the peace in domestic life, save embarrassment (to others as well as oneself), calm the frightened, reassure when reassurance is vital, cover important information that the enemy might be seeking, and much more. Lying is not always a bad thing and is sometimes a good thing: though it very much matters what the circumstances are and what case can be made in justification of it, given that the very high value of truth makes the demand for such a justification an exigent one.