Under or overpayments of tax
If you receive a tax calculation from HMRC on a form P800, don't assume it is correct. The P800 form is supposed to be sent to taxpayers who are not required to submit a self-assessment tax return form.
But some people have received both a tax return form for 2014/15 (or a request to complete one online), and a P800 tax calculation for the same year. In those cases something has gone wrong with the HMRC computers, as the P800 form will generally only consider the section of a taxpayer's income which is taxed under PAYE, and ignore all other sources of income.
Some of the P800s for 2014/15 were issued before the P11D forms for that year were processed by HMRC, in which case the P800 tax computation will omit benefits and expenses, or include benefits and expenses for 2013/14 instead of 2014/15. In other cases inaccurate amounts of tax underpaid for earlier years may be included.
If you have received a P800 calculation you may also receive a cheque for a tax repayment. Please don't cash that cheque until you have checked the tax calculation carefully against your P60 and P11D for 2014/15, and asked us about any odd figures. HMRC won't send us a copy of the P800, so we will need sight of your personalised tax calculation to check the figures.