Fixed-term Parliaments Bill

The hon. Gentleman is making another fine speech, which I am always glad to hear. He spoke about the mandate for constitutional change and the previous mandates that previous changes have enjoyed. Does he agree that it is important to have a mandate not only to introduce a change in the constitution such as that proposed, but to entrench it? Without such a mandate, is there not a danger that future Governments may feel that they have the authority to introduce such constitutional changes to their own benefit, much as the present Government are seeking to bring in a constitutional change through the measures in the Bill for their own benefit?