Twenty years ago, Tony Blair stunned the political world by declaring his intention to rewrite Labour's hallowed Clause IV and end the party's formal commitment to mass nationalisation. The move, endorsed at a special conference in 1995, was a defining point in the birth of New Labour. Ever since, leaders of all parties have been challenged to display similar daring and achieve their own "Clause IV moment".

Today, following his election as Scottish Labour leader last Saturday, Jim Murphy will seek to do quite literally that by vowing to rewrite Clause IV of his party's constitution. Mindful of Scottish Labour's tarnished reputation, which allowed the SNP to win majority control at Holyrood (and to surge in the polls), the former cabinet minister is attempting to redefine his party's purpose for the post-referendum era. He will say in a speech in Glasgow:

Once Labour’s challenge was that too many people felt they could not be Labour and make an aspirational choice. Today Scottish Labour’s challenge is that some people feel they can’t be Labour and make a patriotic choice. The change we need goes deeper than the leadership style of a new team. If this is to be a genuinely fresh start for our party we need to make more fundamental change. That is why I can announce that I will ask Scottish Labour’s Conference in March to agree a new 'Clause IV' for our Scottish constitution. A new statement of purpose for a new generation in the Scottish Labour Party. It's the biggest change in Scottish Labour's history. This is a 'Clause IV' moment for a different time and a different purpose. Tony Blair rewrote Clause Four of UK Labour to bring us closer to the centre of politics. I want to rewrite 'Clause IV' of Scottish Labour to bring us closer to the centre of Scottish life.

Murphy will go on to outline five principles for the new Clause IV. They are:

1. Making it clear that Scottish Labour is a "patriotic party"

Murphy will say: " One: we will make it clear that we are both a democratic socialist party and a patriotic party. We are a socialist party yes, but we recognise that our political faith grew out of something deeper which is ingrained in our Scottish character. It was there before our party in the ethics of Burns' poetry, the economic vision of New Lanark, the actions of the Highlanders who took on brutal landlords. A belief that we stand together, look after those who need our help, and make sure that everyone gets a fair shout."

2. Declaring Scottish Labour a party that "represents Scotland first"

"Two: while we do not give up on our belief in active solidarity with people across the United Kingdom and around the world, we will make it clear that this is complementary to, and not in conflict with, the national interest of Scotland. "We will declare ourselves a party that represents Scotland first, and where, as Scots, we work with others to achieve the potential of all."

3. Committing to "total devolution" of policy making in devolved areas

"Three: we will set in stone the total devolution of policy making in devolved areas. Policy will be made in Scotland, for Scotland, by our Scottish Party, putting the needs of Scotland first."

4. Committing to a "permanent and powerful" Scottish Parliament

"Four: we will make the same commitment in our own party constitution, as the Smith Agreement did in the UK Constitution, to a permanent and powerful Scottish Parliament."

5. Renewing Labour's mission for "a more equal and fairer society"