HM Revenue & Customs (HMRC) admitted today that they have sent out incorrect tax bills for the second time in four months. This essentially means millions of UK workers face uncertainty about their tax payments. Only in June this year, HMRC announced 5.5 million workers paid the incorrect tax in 2013/14 by an average of £300. Those affected were sent new bills; however, a leaked email declared that even these were wrong and the tax now needs to be recalculated for a third time. Last night, HMRC admitted that, although they are unsure of the exact number of workers affected, they expect it to be ‘well under 100,000’. They have also stopped sending repayments until the blunder is resolved. The miscalculations are said to have occurred due to employers not updating HMRC with the latest changes affecting their employee’s salaries. Real Time Information (RTI) reporting, which was introduced in April 2013 and requires employers to report PAYE information in real time was thought to limit these errors. However, these recent mistakes evidently show that the system is still far from perfect. HMRC have apologised for the mistake and aim to resolve the error within the next six to eight weeks. Tax payers who question their bills have been advised ‘not to repay any underpayment’ of tax.