The quick answer
A Corporation Tax Liability is owed by a limited company on either tax on trading profits, tax on a capital gain or tax on a distribution often called a section 455 liability.
A section 455 liability arises from an overdrawn directors loan account not paid back within nine months of the company year end.
In more detail
Corporation tax is payable on trading profits or taxable capital gains made by a limited company nine months after the year end. Most companies pay tax at 19%. Larger companies have to pay their corporation tax quarterly. The calculation is made by your accountant or other professional adviser and notified to H M Revenue and Customs on a CT200 form. If you pay the tax late or send that form in late, there are penalties and interest.
If you have an overdrawn directors loan account, which is where the director has been paid too much and owes the company back money, then there is a tax charge applied called a section 455 tax liability. When the overdrawn loan is repaid by the director the tax is repaid.
If you do not pay H M Revenue and Customs the tax due, they are one of the most likely creditors to threaten winding up against you, which is a forced or Compulsory Liquidation. To wind your company up they will send you repeated written warnings, which if you ignore will finally lead to them petitioning by asking the Court for a hearing to wind your company up.
A Word Of Advice
Do not let H M Revenue and Customs wind up your company without taking professional advice on what to do first.