Corporation Tax is charged on the company's taxable profits

1.5 Taxes that a consultant may have to pay

If you have your own company then you have to

work out the company's corporation tax liability
pay the tax without prior assessment by HM Revenue & Customs; and penalties may be charged if the return is not lodged by the statutory filing date, normally 12 months after the end of the accounting period.
pay the corporation tax within 9 months and a day of the accounting reference date.

Reducing profits by claiming expenses and making pension contributions will decrease the corporation tax liability.