Overview

• About four million P800 and Simple Assessment letters are being issued between June and August to explain how to claim refunds or pay tax owed.
• Bank transfers claimed via the HMRC app or personal tax account typically arrive within five working days, while cheque payments take around six weeks, and claims require the P800 reference and a National Insurance number.
• Tax calculation letters go to employees and pension recipients, whereas Self Assessment customers have over- or underpayments adjusted automatically in their bill.
• Common causes of overpayment include incorrect tax codes, being paid by two employers in the same month when changing jobs, starting a workplace pension, or receiving benefits such as Employment and Support Allowance or Jobseeker’s Allowance.
• HMRC says it may send text reminders after letters but will not ask for payments or personal details, directing people to use official Gov.uk services or the HMRC app.