Well it might be a good idea to have one. Looking at what are generally thought to make up our existing constitution i.e. Magna Carta, Bill of Rights, they seem most notable for their distinct lack of influence on our justice system. Trial by Jury, the Right to Silence, non-forfeiture of goods without conviction all seem to have either been put to death or on the way to it.
What is apparent though in those old pieces of history, is that they were always about challenging the power of whoever was in charge; Magna Carta limited the power of the monarch against the people, well at least against the Barons anyway. The Bill of Rights also limited the Monarch's power, but this time, in favour of Parliament. This set in motion the transfer of power and state building to Parliament, which now occupies the position once held by the Monarch.
So, let's have a written constitution to reflect our modern society. But given our history of always having to challenge the powers that be in order to secure what we believe to be our freedoms I would think asking that power, to give us a constitution seems rather bizarre.We need a constitution to protect ourselves from those who rule. Therefore, we need to write it for ourselves and impose it on any would be Parliamentarian, along with a Constitutional Court to prevent said Parliamentarians from putting it away in drawer, forgetting about it, re-writing it, adding to it while we're all asleep and generally not giving a stuff about it once they think we're all happy that they condescended to let us have one.
I intend to look more closely at our so-called protections from authoritarian rule via our so-called existing constitutions and ask whether or not it does what it says on the tin.I shall post my conclusions on here for others to dissect and discuss. In the meantime let's have a poll to see just how much support there is for a modern constitution.