We have recently become aware of fake APNs being issued.
They come from an email address noreply [at] hmrc-email.co.uk and are headed “Accelerated payment notice”. They typically state a date, a reference number, an amount of tax owing, and the tax year to which it allegedly relates. An attachment is sent with the email. HMRC have confirmed that these are indeed phoney APNs.
HMRC’s advice is not to open the attachment or click on any links. HMRC publicises details of current known scams on its website here.