fines in in corporation tax

I think you may be referring to interest that is payable on overdue tax and receivable on overpaid tax. In corporation tax such interest is INCLUDED in deriving the Interest income assessment (sometimes referred to as the NTLR – Non Trading Loan Relationship – assessment), interest receivable increasing and interest payable reducing this assessment. In income tax such interest is EXCLUDED from the income tax computation with no assessment on interest receivable from HMRC and no deduction for interest payable.