HMRC can go back up to 21 years of trading history. But if you have had a different business in the last 20 years, your advisor or accountant can communicate with HMRC about a starting point. It’s the job of your tax accountant to bring down the tax investigation to specific years, so he can concentrate on the actual period when income has not been disclosed in accounts and tax returns. As a rule of thumb, HMRC will ask the last year when all tax affairs were in order. To determine this, our tax accountants look for the earlier year. If they see any discrepancy, they will go further until they reach a point where tax affairs are in order and agree on the tax years to be investigated with HMRC. If you have been insolvent or bankrupt in the past, the start date will be from the date you started the business after bankruptcy.