Before going in to address a class of first year law students at Aberdeen University, last November, the head of the Law School took me aside and said, “Just to be aware. Most of your audience can’t remember a Scotland without a Scottish Parliament.” And, of course, these students were only about four years old, when the first elections to that Parliament were held fifteen years ago last week.

To those of us who campaigned so long and hard to create the Parliament, it doesn’t seem so long ago. But that a new generation of young Scots takes the Parliament’s existence for granted is a welcome affirmation that we achieved the permanent legacy of a transfer of power that has brought government closer to the people of Scotland.

For those who have always known a Scottish Parliament, they have lived in times when we have had the best of both worlds. A strong Scottish Parliament which shapes our domestic agenda while working together across the UK to unlock shared economic and social advancement.

Before the creation of the Scottish Parliament, much of the constitutional debate had been around which powers should be transferred from Westminster, not how they might be used. The devolution settlement put that issue to bed for a time. As a member of the first coalition government in Scotland, I was one of those grappling with the question of what we did with those powers.

As Liberal Democrats, we know that that power is not an end in itself. It is a means to deliver the kind of social change and Liberal reform that Scotland needs. It is through the exercise of power that we can support individuals and families, help businesses and build a fairer society – that is what we sought to achieve in government.

Different parties have different values and different priorities. That is the nature of politics. But working with colleagues in Labour and across the Parliament we were able to pass key legislation that is as important today as it was more than a decade ago.

The first Act plugged a legal loophole which had led to a man who’d pled guilty to killing a neighbour being released from the State Hospital. Devolution gave us the powers we needed to act expeditiously. We then legislated to implement a Scottish Law Commission report to simplify the law relating to adults who lacked capacity to enter into legal transactions.

There followed legislation to give communities the right to buy land and individuals the right to responsible access over land. Other early successes of devolution included free bus travel for older people, free eye and dental checks and the abolition of tuition fees.

Debate over issues like free personal care for the elderly was fierce. But Liberal Democrats, with the support of many within Labour and the other parties, were able to make the case for a policy that has benefitted thousands of older citizens over the last decade.

Arguably, the most significant measures were the introduction of the single transferable vote for local elections and the ban on smoking in public places. England later followed the trail blazed by the latter; but sadly – as we’ll see later this month – still retains the much less democratic first-past-the-post system for council elections.

In 1999, Scotland faced different demographic and health challenges to the rest of the UK. That is still the case today. But devolution gave us the power to design a Scottish solution to the unique circumstances that we faced.

A proud Scottish Parliament had the powers to take big choices on policies that continue to make a huge difference to the lives of people around Scotland. And just as today, Scotland benefited from the strength and stability that we took from being part of the UK.

Policies taken forward in the Parliament have helped build a consensus that decisions over things like health, education justice and transport should be taken here in Scotland. That is the real legacy of the devolution settlement and it is something that Liberal Democrats welcome.  After all, Liberals have backed Home Rule and the decentralisation of power since Gladstone’s Midlothian campaign in 1879. And since 1999, Liberal Democrats have continued to make the case for a stronger Scottish Parliament, building on the successes of devolution while protecting the positive things we share as part of the UK.

It was a Liberal Democrat Scottish Secretary, Michael Moore, who took the Scotland Act 2012 through the UK Parliament, extending the tax powers and accountability of the Holyrood Parliament. The latest report from Sir Menzies Campbell’s Home Rule Commission report shows that we are still leading this debate.

All three UK parties have made it clear that further devolution for Scotland will be on the agenda in the 2015 election manifestos, if Scotland votes to stay with the UK. There is a growing consensus that a no vote in September will not mean no to change. A positive vote to remain part of the UK offers Scotland the best of both worlds. A stronger Scottish Parliament and the strength, security and stability that comes from being part of something bigger. More powers for Scotland and more opportunities for businesses as part of the UK family.

Come September, I hope that the Law students I met in Aberdeen vote to build upon this progress  by voting to remain in the UK. That would be a positive change which builds upon Scotland’s proud history of devolution and enables a future where we can have the best of both worlds with a stronger Scottish Parliament which shares risk and reward across the broad UK shoulders.

The first 15 years of devolution have been good for Scotland. The next 15 years represents an inspiring opportunity to build upon that progress.

* Jim Wallace is leader of the Liberal Democrats in the House of Lords and was Deputy First Minister of Scotland from 1999-2005.