Threshold Income for pension Annual Allowance

When giving letting income for the threshold income calculation, can the letting income mortgage interest tax credit be included to reduce the letting income?

Hi Paul,
Thank you for your question.  
Interest on mortgage payments is not allowable as an expense.
They are used instead as a reduction to your tax liability at 20%.  
You can find guidance on how to work this out at:
Tax relief for residential landlords: how it's worked out.
Thank you.