If you owe your company money, your personal and company tax responsibilities depend on how the loan is repaid.
Option 1 - you repay the loan with 9 months of year-end
Pay your company interest at the HMRC official rate - currently 2%
Option 2 - you do not repay the loan within 9 months
In addition to the interest at the HMRC official rate, use form CT600A to show the loan amount owed at the end of the accounting period. Pay 32.5% corporation tax on the amount outstanding. You can reclaim the tax when the loan is repaid, but not the interest.
Option 3 - the loan is "written off"
Put the loan amount written off through the company payroll and pay any PAYE due to HMRC