It is therefore open to the Imperial Parliament at any time to repeal or amend the Government of Ireland Bill after it has become law. On the other hand, the Irish Parliament will have no power, except in so far as such power is conceded by the Act itself, to alter its provisions. This is stated in the Bill itself,(17) but the statement is superfluous. It follows from the doctrine of the supremacy of the Imperial Parliament that statutes of that Parliament can only be repealed by the Parliament itself. No constitution granted to a British Colony, however large the grant of self-government it contains, can be altered by that colony unless the power to alter it is expressly conceded. Such a power, when the Constitution itself does not prescribe some particular method of constitutional amendment, has indeed been granted in general terms by Section 5 of the Colonial Laws Validity Act, but this Act could not apply to Ireland, which is outside the legal definition of a colony contained in the Interpretation Act of 1889. The only powers of constitutional amendment which the Irish Legislature will possess are those expressly conceded in Clause 9, which enables it after three years from the passing of the Act to deal with the franchise and with re-distribution.
The Irish Parliament will, of course, have power to repeal any existing Acts of the Imperial Parliament in so far as they relate to Ireland, and do not deal with matters exempted from its authority. It would be impossible for it to legislate for the peace, order, and good government of Ireland if it had not this power, and the power is implied in the general grant. But if the Imperial Parliament chooses to continue to legislate for Ireland, even in matters in regard to which the Irish Parliament has been empowered to legislate, such Imperial legislation will be of superior obligation. This is also a corollary of the doctrine of the supremacy of Parliament, and it was not necessary to state it in the Bill.(18) The grant of particular legislative powers to Ireland does not prevent the Imperial Parliament from subsequently legislating in derogation of those powers. The supremacy of the Imperial Parliament is as inexhaustible as the fountain of honour.