A referendum on the European constitution could serve two functions: to guide parliament on ratification of the proposed constitutional treaty; and to generate a debate about Britain’s place in Europe.
The absence of a coherent written constitution for the United Kingdom means that it is not possible to give a definitive answer to the question of whether a referendum is formally necessary. The fact that European integration advances by stages reduces the significance of each individual stage but does not diminish the importance of the overall process. If the next set of modifications to the Brussels system of decision-making do not amount to a revolution, the fact that the European Union is ready for a constitution deserves the broadest possible public discussion.
This is the reason for a renewed debate about the future of Europe and Britain’s place within it. The referendum in 1975 did not settle the question: it is still a live issue. It would be possible to initiate such a debate without holding a referendum but the government does not appear to have a taste for this.
If there is to be a referendum on the constitution, there needs to be a dose of honesty and humility about the decision to be taken. It is not for the British to decide whether or not the rest of Europe continues to integrate on a federal basis. They can only decide whether or not they wish to participate themselves.
The choice to be made in a referendum is therefore not between the new constitution and the status quo, but between the new constitution and leaving the EU altogether. The other member states that have participated in the convention and the IGC and accepted the terms of the new constitution should not be prevented from adopting it because of a British no vote. If the British vote Yes, then they will retain their place in the Union. If they vote No, they must be ready to leave the EU and negotiate some new kind of relationship from outside it.