He addressed the ‘Wales and the changing Union' event organised by the Institute of Welsh Affairs.
The First Minister said:
“Some people may say that constitutional debates are only of academic value, but I have to disagree. The outcomes of these debates will impact directly on how we as a Government deliver our services to the people of Wales.
“We are on the brink on huge constitutional change in the UK. There is a strong case for reforming our central institutions to reflect the emerging reality of a looser UK. We should be moving forward as a Union to a constitution that reflects the 21st century, not the 19th.
“We must consider the prospect of a written constitution which in part would define the relationship between the Devolved Administrations and UK Institutions. The UK has changed beyond recognition over the past 15 years and it is time that our constitution recognised this.”
The First Minister also touched upon the implications of Scottish independence:
“The matter of Scottish independence is one for the people of Scotland. But I believe in the United Kingdom and I strongly believe that we, as a Union, are stronger together than apart. If the people of Scotland vote in favour of independence the shape and constitutional make-up of the UK will be dramatically changed.
“Equally, if the vote is against independence there is still the prospect of substantive constitutional change in one part of the UK that potentially will impact on all other parts of the Union. I have therefore called for a Constitutional Convention that would enable all four countries of the Union to discuss its future. I have written to the Prime Minister on this issue, and await his response.”
The First Minister also set out his views on the strong case for some taxes to be devolved for Wales and the need for the Welsh Government to have new borrowing powers for capital investment.