09/09/2026
Did you pay your second payment on account on 31 July?
Payments on account are the two advance instalments towards your personal tax bill, one due 31 January and one 31 July. Everyone remembers January. July slips past.
If not, HMRC has been charging you interest every single day since 1 August.
The rate is 7.75%. In real terms:
£1,000 owed = 21p a day
£5,000 owed = £1.06 a day
£10,000 owed = £2.12 a day
Not a disaster. But it's money leaving your business for nothing, and it doesn't disappear — it turns up again in January on top of everything else.
If you can pay it, pay it and the interest stops. If you can't, HMRC's Time to Pay scheme is far less scary than people expect.
And if your income has dropped this year, the amount they've asked for may be too high. Worth a check.