Trading losses may be carried back to set against previous year profits by completing and submitting the current year Company tax return and Amending the previous year tax return as follows:
Complete the current year form:
1. Tick box 45, “Claim or relief affecting an earlier period”.
2. Complete the Losses Worksheet including the Losses to Carry Back box.
3. Generate the iXBRL Computation file and reattach.
4. When the return is complete, submit as New (unless it is being amended).
Update the previous year form:
1. Tick box 40, “A repayment is due for this return period”.
2. Enter the corporation tax previously paid in box 595, “Tax already paid (and not already repaid)”
3. Complete the Losses Worksheet with the losses carried back amount entered in the Losses Brought Back box.
4. Regenerate the iXBRL Computation file and reattach to the return.
5. Resubmit the tax return as an Amended return.
For a limited period, losses can be carried back two further years. Further details are given in the FAQ: