First Minister travels to Scotland

Carwyn Jones' speech in Scotland tonight comes after he made no secret of the fact that he was very reluctant to travel north until Westminster gave him a good story to tell.

In other words he was waiting for the UK Government's response to the Silk Commission before going to bang the drum for the Union.

He'll say that a strong Scotland in a strong UK is a positive choice in the referendum. The subtext from this will be that even if you stay inside the tent, you can still cut a decent deal with Westminster.

It follows the announcement by David Cameron and Nick Clegg earlier this month that the Welsh Government will be given some tax varying and borrowing powers. Westminster gave Cardiff Bay pretty much all of what it really wanted.

As a result, when the Prime Minister and his deputy were at the Assembly, one of the key areas of discussion behind closed doors was for the First Minister to travel to Scotland to boost the Unionist cause.

As the most senior Labour leader of a devolved nation, Carwyn Jones can do and say things which the Prime Minister can't as a Conservative visiting a country where there's only one Tory MP.

In that sense the shadow of Scotland loomed large over events at the Assembly at the beginning of the month.

It also hung in the air during the press conference on Monday where Chief Secretary to the Treasury Danny Alexander joined the Welsh Secretary David Jones and the Welsh Government's Finance Minister Jane Hutt to give more details of the tax varying powers.

The most significant development was the news that any powers over income tax would not involve the ability to vary income tax bands independently from each other.

It's what's called the lockstep model and it's what is due to be introduced in Scotland in 2016 even if there's a no vote next year.

It delivers a very crude way of changing income tax levels and makes it impossible to target particular tax bands. Jane Hutt called it a missed opportunity. Carwyn Jones remains to be convinced of the case for Wales to have income tax powers at this stage anyway - and this makes it more unlikely he will change his mind anytime soon.

Whatever the rights and wrongs, the truth is that everything relating to devolved issues at a UK level is seen through the prism of Scotland at the moment and Wales is not going to get anything that hasn't been offered to the Scots already.

Carwyn Jones' visit takes place a matter of days before the SNP-run Scottish Government publishes its long awaited White Paper which is the opportunity to put forward its case for independence.

This is a huge moment in the campaign so far. The intention is to try to answer the million and one questions people have about what would happen in the event of a yes vote.

Now of course the White Paper is not going to answer all the questions and I suspect the big battleground next week will be to what extent the SNP can justify not filling in potential gaps in areas as varied as pensions, currency and nuclear capability.

In the context of such a crucial moment, the question is whether the arrival of Wales' First Minister will register with Scots.

But on one level I can see why his visit is significant.

I was in Scotland for a week in September and a major criticism of the Better Together Campaign then was its perceived negativity. The SNP have nicknamed it "Project Fear."

Carwyn Jones' speech does at least give the campaign what it will see as a positive story to tell the Scots about the Union and the potential to develop Scotland's powers within it.