The requirement for legislative authorisation
33.8The rule that legislation is necessary to give legal authority to taxation and expenditure is based on ancient constitutional usage.1 The Commons have from the earliest times claimed predominant rights—financial privilege—in relation to such legislation. The right of the Lords to initiate such legislation was denied; their power over them was reduced to the simple giving or withholding of assent; and a special enacting formula was employed which explicitly asserted the rights of the Commons.2
The modern procedure in respect of privilege arising from the role of the House of Lords in relation to bills authorising expenditure and taxation is dealt with in Chapter 37.
Although as a general principle legislation is needed to give final sanction to parliamentary grants of Supply and Ways and Means, since 1913 a temporary and provisional validity has been conferred by statute on certain Ways and Means resolutions imposing taxation (see para 36.36 ). These powers are regularly used as part of the annual Budget process, in order to allow immediate effect to be given to changes in, for example, excise duties.