What a difference a few hours make. In the morning, Jack Straw’s heavily qualified hints about working towards a written constitution were welcomed by Unlock Democracy, a leading reform group. Then, in the afternoon, Mr Straw’s full speech, entitled “Modernising the Magna Carta”, received a more hostile response: “what a load of cobblers,” as the OurKingdom website put it.

At stake is whether Britain keeps parliamentary sovereignty, or rather supremacy, or moves to a constitutional or rights-based democracy, as reformers want. The term “written constitution” is anyway misleading, as Professor Anthony King points out in his The British Constitution, the best and most readable recent book on the subject. Large chunks of Britain’s small c constitution are written down in various laws: what we do not have is a capital C Constitution, codified and interpreted by judges.

The reformers see Mr Straw as the upholder of Parliament. He emphasised that the new supreme court should not undermine the sovereignty of Parliament: he is wary of judges, rather than politicians, taking decisions about the allocation of resources.

That does not mean that Mr Straw is opposed to change. Far from it. The thrust of his speech was about the proposed Bill of rights and responsibilities, building on the Human Rights Act. This will involve a mixture of symbolic or declaratory principles on social and cultural issues and fully justiciable rights. “We need now to think very carefully about whether a British Bill should be a step towards a fully written constitution.” He envisgages a journey of ten to twenty years away from the traditional view of parliamentary supremacy, during which “building blocks” of a constitution are put in place, aiming towards a single formal document. The key, momentous decision will be over the role of judges.

The other main question is how decisions are taken. The reformers want to replace parliamentary democracy with popular sovereignty via binding referendums and citizens’ conventions. The divide between participatory and representative democracy has become central in the debate. Michael Wills, who is handling constitutional reform at the Ministry of Justice, emphasised that “representative democracy, and therefore Parliament, must remain at the heart of the governance of this country”. He gave warning of the dangers of plebiscitary democracy, not least because of the ability of powerful interests to mobilise opinion via the internet.

None of this excludes the use of citizens’ juries and other consultative and deliberative mechanisms to give voters a greater say in the development of policy, rather than just voting every four or five years. This still leaves the final decision with Parliament on all but a few basic constitutional issues. The deliberate fuzziness by successive prime ministers about what these basic issues are has landed the Government in such controversy over the Lisbon treaty.

The constitution is in flux: we now have a hybrid, neither full parliamentary sovereignty nor codified. The main gap is to show what changes mean for voters.

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