Well, well. This is interesting. The renewal of Trident is to be debated at the Scottish Labour Party conference, according to the new Scottish leader, Kezia Dugdale. The times they are a- changin'.

It's a move that will worry the present party leadership in the UK, who'll insist that Trident is not an issue for the Scottish party because defence is reserved to Westminster. The SNP think she isn't serious.

But CND are certainly excited. The last time the Scottish Labour Party debated Trident more than 20 years ago, conference opposed nuclear weapons. In fact, that vote has never been reversed. So if Ms Dugdale is serious this could be a breakthrough for unilateralists. If Labour voted against renewal, their leader could hardly ignore it.

During Ms Dugdale’s campaign she insisted that the old rigged Labour politics was finished and that the Scottish conference would become a proper democratic policy forum. She hopes to draw a contrast with the SNP conference where certain issues, such as a second referendum, have been curiously absent from the conference agenda.

Wendy Alexander's former spin doctor, Simon Pia, told BBC radio yesterday that only through independence on issues such as Trident will Labour combat the dominance of the SNP.

But it is a sensible move in terms of her own party. Unilateralist Jeremy Corbyn is tipped to win the Labour leadership, possibly even in the first ballot according to the latest YouGov/Mirror poll. It would be bizarre if the UK Labour turned against weapons of mass destruction on the Clyde and the Scottish party remained doggedly in favour of them.

In the past, the MSP for Dumbarton Jackie Ballie has had an arm lock on any move against Trident because of jobs. In Better Together, Labour claimed that independence would jeopardise more than 6,000 jobs at Faslane, where Britain’s Vanguard submarines are based, and Coulport, where the nuclear warheads are stored. This was an inflated figure and the numbers involved directly with the nuclear warheads are much smaller.

But jobs were always a disreputable argument. If no weapon system could be abandoned because of job losses we’d still be building Dreadnoughts. The argument about nuclear weapons is and always will be a moral one: it is that weapons of mass destruction that target civilians are an abomination and are illegal under international law.

Contrary to popular belief, Britain accepts that weapons of mass destruction are morally indefensible. We are repeat signatories of the 1968 Nuclear Non Proliferation Treaty (NPT) which commits the UK to work “in good faith” toward nuclear disarmament. Successive governments have insisted that we have honoured this by building down our arsenal.

But renewal of Trident in 2016 puts Britain on dodgy ground. It is hard to claim that we are phasing out nuclear weapons when we are busy building new ones. Tony Blair got round this by insisting that it is not a new system, just a different version of an old one.

But this cuts both ways. Trident is indeed an obsolete weapons system designed to destroy Russian cities. It can't ever be used for its original purpose. So is there much point in renewing it?

Every time there is an international crisis, such as in the Ukraine, Trident supporters insist that this is a “dangerous world” and that “we don't know what the future may bring”. Indeed we don't, but we can make an intelligent guess.

No one in their right minds would suggest using Trident against Vladimir Putin or IS or the Taliban. What Britain does need is a properly-equipped conventional defence force able to deal with real conflicts. Since the end of the Cold War Trident has been a £100 billion anachronism.

Nuclear weapons are anyway largely about international prestige and Britain's place on the UN security council. But that is no longer such a big deal. By honestly phasing out nuclear arms, Britain could arguably make a bigger impact on the world stage. We cannot go on demanding that countries like Iran halt nuclear programmes when we are renewing them ourselves.

If the Scottish and UK Labour parties turned against renewal of Trident – and the Liberal Democrats are reviewing their stance also – then there could be a strong significant anti-nuclear presence in Westminster for the first time in three decades. David Cameron would still hold sway in any vote on renewal and Labour might split. But it we could be entering a new game, north and south of the Border.