Following a vote for independence, the Scottish Independence Bill would be introduced to the Scottish Parliament. It would form the interim written constitution for Scotland until the constitutional convention, which would be established by the Scottish Parliament elected in May 2016, prepared a permanent constitution for Scotland.

As First Minister Alex Salmond outlined last year, that constitutional convention will involve input from a wide cross-section of civic Scotland, articulating the nation’s values and enshrining them in a permanent written constitution.

Ms Sturgeon said:

“Today, the date which will become our independence day following a vote for independence this September, I want everyone in Scotland to consider who we are as a nation and what we have the potential to become.

“Independence is not a historical argument, it is the opposite – a live and vital opportunity to chart our own course, to give us the power to determine our own future and build the kind of country we can all be proud of.

“A written constitution is an important part of a nation’s identity – it defines who we are and sets out the values that we hold dear. Currently we are without a written constitution, and the UK is the only country within the European Union or the Commonwealth that does not have a written constitution or a constitution Act – that is a democratic deficit an independent Scotland will not replicate.

“It is a cornerstone of Scottish democracy that sovereignty rests with the people. That is why we want to make the drafting of our permanent written constitution an inclusive process involving all the people of Scotland – it must be a constitution by the people, for the people – articulating Scotland’s values, enhancing our liberties and defining our responsibilities.

“I believe the process of drafting our constitution will energise and inspire people across the country - woman and men, young and old, rural and urban, people in all the diverse communities that make up modern Scotland. It would be an exciting and unique opportunity to shape our nation, celebrate and protect our values and commit ourselves to building a better country.”

In her Cardiff lecture, Ms Sturgeon will also set out the economic and social case for Scotland becoming independent. She will argue that the notion of the UK as a partnership of equals is being undermined by those leading the argument against independence. And she will say that the social union between Scotland and the other nations of the British Isles will be strengthened, not weakened, if Scotland becomes an independent country.