Millions of pensioners and savers may have received an unexpected tax bill over the summer from HMRC, under the taxman’s simple assessment system. The taxman has sent 1.4 million simple assessment letters to people who owe money over the past month. Anyone who receives a simple assessment letter and wants to find out more is encouraged to go online to GOV.UK, where there’s plenty of guidance to help." The simple assessment letter should provide you with an assessment of any tax you owe and how it was calculated. The only way HMRC will contact simple assessment customers is via a letter or through their Personal Tax Account.