Thank you very much for the question and the opportunity to provide some further clarity on this issue. Rhun ap Iorwerth is right: this was a historic thing that we did on 6 April in terms of setting our own tax rates, and it is important that people are able to have full confidence in the system that underpins that. I think it might be helpful if I just set out what happened, to bring us to where we are. 

So, HMRC assigns the correct tax codes to all UK taxpayers through the annual coding exercise. HMRC then issues a P9 form to employers, which confirms the tax codes to assign to each of their employees. It’s then the responsibility of the employer to correctly apply this tax code using whatever software or process that they have adopted. And some payroll providers, in this case, incorrectly applied the S code to Welsh taxpayers. We're awaiting further detail on how this happened, but it does appear that, in some cases, payroll providers haven't updated their software to enable the C code to be applied.

That’s particularly disappointing because HMRC did do extensive work with employers and payroll software providers throughout the preparations for the introduction of Welsh rates of income tax, using their established communication channels and also bespoke presentations, as well as providing technical specifications and test data to ensure that employers and payroll software providers had all the information that they needed. So, there’s no evidence at this stage that HMRC made any errors in allocating the codes to individuals. As I say, it’s disappointing that this error occurred, but beyond that, I think that we can say with some confidence that everything else went smoothly, so I think that certainly is a positive.

In terms of the actions: one of the things that we set out early on, before WRIT came into place, was that there would be the system tests. One of those will be undertaken in June and that's the earliest date that the relevant data will be available for all employers because of the deadlines for employers to submit their payroll information to HMRC. So, once HMRC has performed these checks, we'll be able to identify any inconsistencies and then identify those employers who will need to update their employees' tax position.

Rhun ap Iorwerth is right to say that we're not talking about large financial sums. So, typically, where taxpayers have underpaid tax, or been overpaid, they would have been underpaid by no more than £2 or where they'd overpaid, it would be by no more than £10. And in some cases, even though taxpayers had the incorrect code, they would have paid the correct amount of tax.

All errors will be resolved by HMRC, so there's no activity or no action required on the part of taxpayers, and obviously, I'm very keen to keep colleagues up to date in terms of any further developments and certainly once we have the results of the tests, which will be undertaken in June.