Principle of Legality - Constitutional Law

Constitutional Law

The principle of legality can be affected in different ways by different constitutional models. In Britain under the doctrine of Parliamentary sovereignty, the legislature can (in theory) pass such retrospective laws as it sees fit, though article 7 of the international convention on human rights, which has legal force in Britain, forbids conviction for a crime which was not illegal at the time it was committed. Article 7 has already had an effect in a number of cases in the British courts.

In contrast many written constitutions prohibit the creation of retrospective (normally criminal) laws. However the possibility of statutes being struck down creates its own problems. It is clearly more difficult to ascertain what is a valid statute when any number of statutes may have constitutional question marks hanging over them. When a statute is declared unconstitutional, the actions of public authorities and private individuals which were legal under the invalidated statute, are retrospectively tainted with illegality. Such a result could not occur under parliamentary sovereignty (or at least not before Factortame) as a statute was law and its validity could not be questioned in any court.