I HATE to bring up Tony Blair so early on, but I’d just like to remind you about something he said in 1997, the day after the Scottish devolution referendum. The then Prime Minister had just flown in from London and, speaking on the streets of Edinburgh, he congratulated the Scottish people on the big decision they’d made. “The benefit of the referendum will not just be here in Scotland,” he said, “but throughout the United Kingdom. The era of big, centralised government is over. This is the way forward.”

Was he right? This year, the Scottish Parliament will be celebrating its 20th anniversary and over the last few days we’ve been learning a bit about how it will mark the occasion. Everyone born on July 1st 1999 (the parliament’s official first day) will be invited to Holyrood; there will also be an exhibition and a photography competition. But will there be some self-examination too? In particular, will we stop and ask if the parliament has lived up to the standard set by Blair in 1997. If the referendum really did signal the way forward for the UK, how far forward are we?

I think the answer is: not far enough – in fact, one of the major problems with the Scottish Parliament and the way it sits in the political landscape is that the benefits of the 1997 referendum have not been felt across the UK in the way Blair hoped they would. The result is that a Scottish parliament based on proportional representation and a Westminster parliament that has largely been unreformed have rubbed up against each other like tectonic plates, with the SNP delighting in every tremor. Why are we caught in endless constitutional debate? It’s partly because Blair’s prediction proved wrong – Scotland has felt some of the benefits of the 1997 referendum while Westminster still hasn’t.

So what have the benefits for Scotland been? The principal one is proportional representation. Whatever you made of the Conservative governments of the 1980s and 90s, they did not have majority support in Scotland; conversely, the swathe of Scotland that did vote Tory was never properly reflected in election results because of Labour’s dominance. The Scottish Parliament fixed all of that and, for the first time, broadly gave expression to the majority views, mostly in the shape of coalitions – it also meant that even when we reached Peak Nat in 2015, there was a balance of smaller parties you don’t see at Westminster.

The PR system, by enabling a progressive majority, has also directly led to some of the Parliament’s best achievements. I’m thinking in particular of the abolition of Section 28, which prohibited the promotion of homosexuality, although the campaign to keep it by the Daily Record and the SNP-supporting billionaire Brian Souter was a reminder that the progressive image of Scotland is often exaggerated. You might also cite the reform of university tuition fees, which was the Lib Dems’ price for coalition. Indeed, the greatest achievements of Holyrood have mostly emerged from coalition and it’s significant that the last two programmes of government, dominated by the SNP, have been the least radical.

However – important as the reforms of the last 20 years are – it’s the constitutional consequences of the parliament that have arguably had the greatest effect on us. In the 1990s there was an idea that the creation of the parliament would end partisan politics and kill off independence as a political force. Instead, 20 years on, partisan politics are as strong as ever and, instead of moving on from independence, we’re caught in an endless debate about it.

The question is whether the Scottish Parliament is really to blame for that and I’m not sure it is – or at least not on its own. The SNP have always promoted the idea that they are the only ones concerned by the democratic deficits that exist in the UK, but it was Labour and the Liberals who led the argument about home rule in the 1970s and 80s. Westminster politicians also used to accuse Scottish politicians and journalists of being obsessed with the constitution at a time when the Scottish Parliament didn’t even exist. In other words, the debate about the constitution was raging long before 1997 – what’s changed is that independence has become the focus of it.

One explanation for this is the way the Scottish Parliament sits within the unreformed system across the UK, which takes us back to those words of Tony Blair in 1997. Blair said the benefit of the devolution referendum would be felt throughout the UK and that the era of big, centralised government was over. But the reality is that the constitutional reform in Scotland has never been replicated across the UK, meaning we have a regressive UK first-past-the-post system (that’s likely to return Tory governments) sitting above a Scottish PR system (that's likely to return progressive governments). To put it another way: we have a system built on differences that the SNP can constantly agitate about.

The only answer is to fix the imbalance with a properly federal system based on proportional representation across the UK. This would mean less chance of a Tory government at Westminster and, by extension, less difference with Scotland. To that extent, reform towards a federal system might also undermine the case for independence by making the UK more responsive to Scottish interests and opinions.

The alternative is to stick with the status quo, but my hope is that the 20th birthday celebrations this year might achieve something significant: even more discussion about the constitution and how to make it better. If you’re horrified by that idea, I understand that, but maybe I should quote another senior Labour man of the 90s – the first First Minister Donald Dewar.

Speaking after the passing of the Scotland Act, Mr Dewar said the debate about the shape of Scotland and the UK should not stop when the doors of the Scottish Parliament opened. And he said this too: it would be even more absurd to believe that the UK can saunter into the future with precisely the same set of arrangements that have served it in the past.