SolvedCTM35130 | Income Tax: collection of tax on annual payments: amended return where company becomes aware of an error
From HM Revenue & Customs · Company Taxation Manual
If, in connection with a CHAPTER15 return for any period, a company becomes aware that
anything which ought to have been included has not been included,
anything which ought not to have been included has been included, or
any other error has occurred,
it must supply an amended return for that period without delay.
Where a company supplies an amended return the necessary assessments, adjustments, set offs or payments or repayments of tax should be made. The resulting liability to tax (including interest on unpaid tax), whether of the company or of any other person, should be the same as it would have been if the company had made a correct return.