Hello, I recently claimed a tax repayment circa £5,000 for the year ended 5 April 2018, for a client. Apparently (although we did not know this at the time of making the claim), he still had a personal tax debt of £5,500 for the year ended 5 April 1998, precisely 20-years earlier. Whilst I appreciate that HMRC could lauch an Enquiry in to a tax payer's affairs going back 20-years, if fraud or some other serious issue was suspected (which does not apply to my client's case), I was not aware they could take a repayment and carry it back to cover a 20-year old tax debt which they had ceased 'pursuing' 17-years ago!
I was under the impression that HMRC could only carry back such a repayment for a very-maximum period of 6 years. If you believe HMRC are wrong to carry it back 20 years, could you please tell me where I can find their rules' guidance notes so I can quote them when challenging this? Or, if you believe HMRC are within their rights to make the 20-year carry back, can you please tell me where I can find those guidance notes? I have searched high and low for such notes and can't find them anywhere.