Paying money back to work, question about tax and NI

[Monstermoomin]

So, my payroll finally got in touch with me and confirmed they have overpaid me around £1360 in OMP in my last payslip. They've said finance will write to me so I can organise repayment and they're going to try to make sure it doesn't just get taken out of my July payslip 🙄

I asked about what happens with the tax and NI I paid on June's payslip given I'll have paid a lot due to significant overpayment (which coincided with the lump sum backpayment for NHS staff), and she just said that will figure itself out over the year, which doesn't fill me with confidence.

Two questions really

1. How much is reasonable to say I will payback monthly. I don't actually have spare money because we're going down to a one earning household. I haven't spent the overpayment because I knew they had done it so it's sat in a poor savings account to try to get some interest.

1. What actually happens about my tax and NI because I've basically been shafted by payroll and they don't even know how or why it happened, but it has.

Thanks for any help!

Personally I would withhold the extra in NI and tax that you paid and give everything else back straight away. When the rest 'figures itself out' I would give the rest back. Personally I would not be willing to be out of pocket for any length of time.

That said I would also contact HR and ask them to work with payroll to provide you an itemized list of when you will get the NI and tax money back. It's complicated I think but there are calculations that finance are able to do and they do have the necessary skills to work out what you will get back and when. If it's not until the end of the year then they can just wait until then for the final installment from you, end of the day it was their mistake.