Can I carry expenses forward from previous tax years?

Hi, I have not made a profit over the income tax threshold for the past few years so I assumed that declaring all expenses would make no difference to me. Someone told me you can carry forward your expenses from the past three years and use them on a year when it would make a difference ie you make a profit over the tax threshold. Is this true? If so how should I proceed? Do I need to / is it possible to amend my tax return to include the expenses that I wish to carry forward and use them on a future tax return? Thanks for any help.

Hi,

Expenses need to be declared in the year that they are incurred and if this creates a loss, then the loss can then be carried forward to set against future profits from the same source of income.

Thank you.