Andrew RT Davies is the Leader of the Welsh Conservatives and Leader of the Opposition in the National Assembly for Wales.

The Welsh Assembly is built on the site of a former dry dock in Cardiff Bay first developed by John Crichton-Stuart, the Second Marquess of Bute – a Scot. Today it is the home to a devolved institution which has grown in stature since its inauguration in 1999 with ever increasing responsibility for decision making which affects the three million people who live in Wales. It is a strong body that encapsulates Wales, build on strong Scottish foundations.

In many ways, Wales has changed because of devolution, yet we remain resolutely within the United Kingdom for good reason – it is a benefit to all of us.

Last week, Wales proudly played host to the largest international summit ever to take place in these islands. The NATO Summit took place in Newport – projecting Wales onto TV screens around the whole world. In a way, it has placed the importance of the United Kingdom at the forefront of many people’s eyes in Wales.

Firstly, 67 world leaders (including President Obama) discussing world affairs in Newport not only shows how important Britain remains as a global power but also that we can facilitate such important summits in our nation, Wales. That wouldn’t happen if we were separate small nations.

Secondly, the summit is a demonstration of Union. HMS Duncan, the British Navy ship being used to host one of the dinners was built partly in Govan and is currently anchored in a docks built by a Scot in the last century!

Wales would be a diminished part of our United Kingdom without Scotland. Not only was modern Wales developed in large part by Scots, but still today we see Scotland as neighbours and not foreign friends. Together we make up a Union of like-mined peoples, where we also act as a balance to our other neighbours in Northern Ireland and England.

Politics aside, Wales and Scotland both have cultures and languages older than any nation in Europe. These aspects of our own nationalities have co-existed with great ease and comfort throughout political changes and throughout the development of the United Kingdom. That is a testament to both the strength of our identities and to the greatest element of the United Kingdom – namely, that it is a union built from its nations, not a union enforced on them.

Wales and Scotland both thrive as nations within the United Kingdom. So what would you gain from being on the outside?

It isn’t for anyone to tell the Scottish people how to vote in the referendum. The decision has to be taken on what they believe is best for them. But consider for a moment how the Union has developed since its origins. We have all got wealthier, our cultures thrive more today than they ever have and our status on the world stage is augmented to levels almost unachievable without it. These factors shouldn’t be taken for granted.

Many people have debated the economics of the referendum debate, and they are important. Further powers to Scotland have been promised by all parties, and the devolution settlement of both Scotland and Wales is changing. But this isn’t a debate purely about economic issues and constitutional pieces of paper – it’s about the heart and the mind.

Be in no doubt – the decisions taken in Scotland will have profound implications on all of us. In Wales, we want you to stay. You help us give balance to our United Kingdom in culture, as much as in economics.