Click on the links below for a detailed analysis of each point:

First and foremost, he asks whether there is such a thing as a 'British constitution'?

Most countries have a written constitution - a single document regulating the powers of its government and the rights and duties of its citizens.

The United Kingdom is one of only a handful of countries which does not.

What the UK does have, however, is a series of conventions which are respected as a fundamental part of the constitution even though they are not enforceable by law.

Conventions evolve over time and the new Labour government has introduced a new element by its increased use of referendums.

Within a year of being elected, the government has organised referendums on important constitutional issues in Scotland, Wales, London and Northern Ireland.

These have formed part of a comprehensive package of constitutional measures contained in a range of important Bills going through Parliament or planned for the near future.

These include regional parliaments or assemblies for Scotland and Wales, a Human Rights Bill and a Freedom of Information Bill.

The UK is a constitutional monarchy and the Queen is often seen as little more than a figurehead. But the Sovereign has important powers which could come into play if potential changes to the electoral system result in hung parliaments.

A constitution needs to put constraints on the government - the checks and balances which prevent an "elective dictatorship" - and in the UK these are provided by three main methods.

As well as the constitutional changes mentioned above, there are the courts and the media.