When limited companies pay tax? Annually, quarterly? Can they decide or is it something that is compulsory?

If your company or organisation has to pay Corporation Tax, you must make sure you pay it on time. If you do not pay on time, your company or organisation will have to pay interest on the unpaid tax.

If your company or organisation's taxable profits are £1.5 million or less:
your Corporation Tax payment is due - in one lump sum - by nine months after the end of your Corporation Tax accounting period

If your company's profits for an accounting period are at an annual rate of more than £1.5 million, you must normally pay your Corporation Tax for that period in instalments. Please refer to HMRC website for more information.