Scotland will get more powers – including control over taxes – if Scots vote No in September. That was the message David Cameron took to the Scottish Conservative Party at its annual conference in Edinburgh today.

The Prime Minister has come under fire from the Scottish Nationalists who have claimed that the only way Scots can guarantee more powers is to vote Yes.

In a clear attempt to undermine this argument, the Prime Minister went further than he has ever done before by promising to devolve more power from Westminster to Holyrood if Scots vote No. He said:

‘The Nationalists want people to believe that this is the end of the line for devolution: do or die, separate or just stick with the status quo. This is wrong.

‘Let me be absolutely clear: a vote for No is not a vote for “no change”. We are committed to making devolution work better still, not because we want to give Alex Salmond a consolation prize if Scotland votes No but because it’s the right thing to do.

‘Giving the Scottish Parliament greater responsibility for raising more of the money it spends, that’s what [Scottish party leader] Ruth Davidson believes and I believe it too.’

Mr Cameron’s remarks were being seen as a clear hint that the next Conservative General Election manifesto will contain a commitment to devolve a large chunk of income tax to Scotland – plus other taxes, probably including air passenger duty but not corporation tax.

The Prime Minister has got close to this before but this was the first time he has been so definitive about backing a ‘devo plus’ or a ‘devo max’ plan for Scotland.

It puts the Conservatives alongside the Liberal Democrats and, probably, the Labour Party too, in advocating a range of new powers for Holyrood. The parties still don’t want to agree publicly with each other but, whether they admit it or not, there is a growing consensus between the main unionist parties on this issue.

Cameron’s speech was almost entirely about the referendum, a trend that will be repeated by all the main speakers at this conference. And there were some good lines in it. The Prime Minister declared:

‘When you look around the world, so often, tragically, neighbourliness has been list and replaced by wars and feuds. We don’t do that. We don’t slam the doors and turn compatriots into foreigners. We work together and we are envied and rightly envied for that.

‘This is a family of nations, argumentative at times, competitive at times, but a family nonetheless.’

Cameron did, however, make one remark which could be considered risky.

Talking about the feeling of being together as Great Britain, the Prime Minister said: ‘It’s not about subjection or colonialism or dry pragmatism, it’s about being part of a bigger team.’

It may have been deliberate to tackle head-on those edges of Scottish Nationalism which believe Scotland is treated like an English colony, but if anything is guaranteed to wind the cyber Nats up to a frenzy it is an Old Etonian, Conservative Prime Minister talking about Scotland and colonialism.

No wonder the Prime Minister was planning to head out of Edinburgh as soon as possible this afternoon.

Tags: Alex Salmond, devo max, devo plus, Devolution, Scotland, Scottish independence referendum