There are two principal reasons, really. One, it would enable us to raise additional revenue for public expenditure to create the kind of decent society we want to be, and to do so in a fairer way by creating a more progressive tax structure here in Wales. So, take that first point—raising more revenue. The problem with the current system of tax devolution that we have is that it makes it very difficult for us to raise additional revenue. We saw an example of why didn't we in the debate yesterday on the income tax rates; we have to stick, at the moment, to the tax bands and thresholds set by the UK Government. And because the lion’s share of the Welsh rates of income tax are raised through the basic rate, we have to use that basic rate to raise the more significant sums, and there is resistance to doing so, because there's no way of directly cushioning the lowest paid. This is why those income tax powers have never been used here since we secured them; that's why Scotland didn't use those income tax powers before 2016, when it was at last given the power to vary income tax bands and thresholds. There was no use of the original right to vary the basic rate by 3p that the Scottish Parliament was given in 1999; no use of the right to vary each band by up to 10p, which they were given following the Calman commission report in 2012—essentially the same power as we have now.

Now, some people have said that the income tax powers that we have now and they had then were unusable. Now, we don't accept that in Plaid Cymru, as we argued yesterday; it's a matter of political will. And at a time of crisis, even given the constraints and the deficiencies, there comes a time where you have to use those powers, for the reasons that we’ve outlined, to defend public services in an age of austerity. But there are barriers, clearly, which make it more difficult than it should be for us to use the powers currently, and you have to ask the Government, if they’re not prepared to use the existing powers—even under these circumstances—what's the point of having them? What's the point of sustaining the cost and the institutional architecture of these powers if they will never be used? And, the consequence of us not using them is that our fiscal capacity, our ability to do what is necessary for our people, will be decided not by us, but for us by a Parliament in another place. That's not a great place for us to be, is it? It will limit our ability to do our work, to deliver on the task of improving the lives of the people of Wales with which we've been charged, because we'll be at the mercy of a Westminster consensus that believes that a Nordic level of public service is somehow compatible with North American levels of tax.

Because Scotland is free to set income tax bands and thresholds, it has been able to use those tax powers; it's got a starter rate, an intermediate rate, which allows it to increase the basic rate in a fair and proportionate way. The Scottish Government's increasing that basic rate: that was the first time that any Government in the UK has increased the basic rate since 1975—a historic moment—because of this flexibility. At the upper end of the income scale, it's been able to increase rates and set thresholds in a way that reflects the income tax structure of Scotland, rather than the UK, and according to the Scottish Fiscal Commission, the divergence between Scottish rates of income tax and the UK tax policy since 2017 is now generating £1 billion extra in revenue for public services in Scotland, and that will rise to £1.5 billion in 2026. These are substantial sums, and the Scottish Trades Union Congress has suggested some additional changes recently: some new bands, and moving the top rate to 48 per cent, as we suggested in our amendment yesterday, which would raise an additional £900 million on top of that existing £1 billion. And if that was applied to Wales, equivalent in terms of our tax base, we'd be looking at an additional £400 million to £500 million next year available to us. So, it raises additional revenue.

Secondly, it creates a more progressive tax structure. The Institute for Fiscal Studies has concluded that Scotland has the most progressive tax structure in the UK, more progressive than here in Wales, and it's done that through a whole series of interventions, consistently now over the last five years, the first in 2017, it diverged there by introducing a lower threshold for the higher rate. In 2019, it didn't increase the higher rate threshold in line with the rest of the UK. Thresholds for the higher and top rate payers were frozen in 2021, et cetera, et cetera. So, over the last five years, the Scottish Government has consistently, at every juncture, created a more progressive tax structure than England and Wales.

The STUC has pointed out ways in which they could go further along this path by increasing the top rate further, as I said, and creating a lower threshold for its payment, plus the introduction of a new sixth rate in between the higher and top rate. It's because Scotland has this flexibility that you can have this kind of progressive innovation. The Institute for Public Policy Research have suggested that you could go even further; you could actually scrap tax bands altogether and replace them with, effectively, a constant gradual increase in the marginal rate of tax. That would be the most progressive system of all, similar to the kind of system that, actually, is available in many European countries. That's what we could do in Wales if we had these powers, and so the rewards there, in policy terms, are very, very clear: substantial additional revenue, plus the ability to create a much more progressive tax structure, and all that that means in terms of socioeconomic impact in a country that, sadly, is blighted by deep, deep poverty. 

Now, the rewards are there. I'm sure that the Minister, when she shares the Welsh Government view, will talk, as she did in committee recently, about the risks. Well, let's look at some of those risks that the finance Minister referred to in committee. In the short run, greater volatility and unpredictability of revenue. Well, let's look at the current system. The Welsh Government—you yourself said that the budget that you now have is worth up to £1 billion less next year compared with when it was originally announced, and up to £3 billion less over the three-year spending review period from 2022-23 to 2024-25. That's the existing system that you're defending, Minister, which actually is volatile and unpredictable. So, that's the system that we have. The system in Scotland allows us to buffer unpredictability, because of their ability to generate substantial additional revenue.

The other risk that was referred to is the long-term revenue risk, the risk of the Welsh tax base growing more slowly. Of course, the flipside to that is that the Welsh tax base could grow faster. In fact, that's what happened, of late, isn't it? The revenues from the Welsh rate in 2021 exceeded the associated block grant adjustment, providing an additional £62 million to fund public services in Wales. But you can mitigate—