Cameron ended his trip to a porridge factory with a wee speech from Edinburgh’s Grassmarket. Shrouded by a carefully chosen view of the castle, he launched, American tourist style, into a lecture on Scottish history. He missed one tale: Just round the corner is Greyfriars Kirk, where the Convananters gathered on 28 February 1638 to sign – some say in blood – their oath against the Catholic Church. The constitutional question has changed a little over the years, but the stage is essentially the same.

The last speech approaching this significance delivered in Scotland by a Tory Prime Minister must have been Thatcher’s ‘Sermon on the Mound’. But whilst she rocked up at the General Assembly of the Church of Scotland to tell a room full of kirk ministers that ‘there is no such thing as society’, ‘Dave’ was, as ever, all PR man: attempting, at least, to show humility.

Whilst Cameron was careful to pay his respect to our nation’s history, Alex Salmond has made a career describing her future. This perhaps shows the awareness each has of the potholes they must navigate in their coming campaigns. Cameron cannot be seen as anti-Scots. Salmond cannot be seen as a petty nationalist.

But the Scottish Social Attitudes Survey from December shows us clearly that this referendum will not be fought on the shifting sands of sentiment. With most Scots willing to change their mind for £500 a year, both sides have a clear case to present: how governance from Holyrood or Westminster would make lives better in Scotland. So, let’s cut through the mush and get to Cameron’s policy points.

For the first time, he reconises addresses the need to look at some shared institutions

“free healthcare for all; in a generous welfare system for the poorest; and championing the most vulnerable on the world stage. A United Kingdom which is not monoglot, monochrome, and minimalist but multi-national, multi cultural, and modern in every way. Our United Kingdom, founded on the strengths, yes, of our constitutional monarchy, our parliamentary democracy, and the rule of law. But it is also the birthplace of the NHS, the BBC and Christian Aid.”

The first thing to note is how uncomfortable is must feel for a radical neo-liberal of Cameron’s bent to make this case. He talks of “ensuring the same disability benefits for those in need from Motherwell to Maidstone” – the very week that the DWP is slammed for forcing disabled people – from Motherwell to Maidstone – into unlimited unpaid work. By the time of the referendum, Cameron is hoping Lansley’s Health and Social Care Bill will have ripped up the NHS in England.

Which leads to the second thing to note: these may be shared cultures, to an extent, but they are not all shared powers. NHS Scotland is already a separate body, and whilst the abstract ‘rule of law’ is something basically every country claims to believe in, the laws in Scotland and England are based on entirely different systems.

If devo-max goes ahead – as he effectively concedes in the speech – then welfare powers will surely move to Holyrood too. On domestic social policy turf, Cameron suffers from the difficulty that he needs to make the case to Scots for a shared state just as he makes the case to the UK for abolishing or at least significantly cutting, most of what it does.

He looks at two other areas – foreign & defence policy, and macro-economic policy. On the former, he struggles again: beyond his attempts to reach to the beaches of D-Day and the trenches of Northern France, he talks about our common efforts in Libya and Afghanistan – neither exactly examples of popular military adventures. If he thinks he can defend the union by pledging to send more Scottish boys to die in foreign wars… He talks with pride of the level of funding DfID gets, but makes no case for why a body which largely distributes fund to NGOs would be weaker if it was two organisations.

Finally, on economic policy, he essentially has three arguments: you need us for trade, you need us to back up your banks, and you need our currency, but need input in its interest rates. The first is of course not much of a point. There is no suggestion that there won’t be a free trade deal between an independent Scotland and the rest of the UK. The other two are more serious issues, and, whilst I believe that there are answers, these need to be articulated by the yes camp if they are to reassure voters that they aren’t being asked to jump into an abyss.

The Westminster pundits loved Cameron’s speech. But most of them have little understanding of or relationship with the Scottish people. There is someone who has a much better relationship with Scots: bookies.

The head of media at William Hill tweeted after the speech:

@sharpeangle: Since [Cameron’s speech] all the money bet on the #indyref has been for Yes vote, now 5/2 from 3/1.

The Grassmarket is where Edinburgh used to hang its criminals. It seems, on the bookies figures, that Dave’s attempt to schmooze the Scots may have gone down like a medieval bread thief…