P800

Why can’t I request a copy of my P800 on HMRC website? I have had a tax code change due to an underpayment for 2022/2023 but no way of checking it

Hi PB55,
 Thank you for getting in touch!
If you're unable to review your 22/23 P800, which confirms your underpayment calculation for that year, you can confirm the amount owed on your Personal Tax Account:
You can sign up for your Personal Tax Account here:
Personal tax account: sign in or set up
Alternatively, you can confirm the amount by contacting us by webchat or telephone:
Income Tax: general enquiries 
Thank you.