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HMRC’s self-assessment tax calculations

03 October 2018 / Tim Good
Issue: 4666 / Categories: Comment & Analysis

That knowing look


  • HMRC provides its Excel calculations to software developers
  • The department publishes a list of exclusions which includes scenarios when the tax calculation is incorrect.
  • The 2017-18 exclusions list has already been amended several times.
  • A correcting program will in due course identify returns with an incorrect calculation and lead to demands.
  • There are ‘unknown unknown’ scenarios that HMRC have not yet included as exclusions.
  • There is one exclusion that has been included in the list incorrectly.

Donald Rumsfeld famously said: ‘There are known knowns. These are things we know that we know. There are known unknowns. That is to say there are things that we know we don’t know. But there are also unknown unknowns. There are things we don’t know we don’t know.’...

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