E Walsh

Hi hoping some people can help with this, Last year I was expecting a large bonus which didn't materialize this year but will likely in coming year; however I paid a large sum in PAYE overpayment the previous year in expectation of this non-PAYE income. The result was that I got interest on this overpayment and after some research it seem that interest paid by HMRC is no considered income for income tax purposes - hence the interest paid by HMRC on this overpayment is exempt from tax. I wish to confirm this to be the case if anyone can help. My three questions are 1. Can anyone confirm that I do not have to pay income tax on interest paid by HMRC on overpayment of PAYE tax. 2. Is there a limit to the amount of money you can overpay tax by and thereby get interest on that sum. 3. Is there a time limit of how long you can leave overpayment of tax money with HMRC before you risk not getting it back when required. Basically I want to leave with HMRC and prepay my potential future tax liability.