Corporation tax is a tax levied in the United Kingdom on the taxable profits made by limited companies and other organisations including clubs, societies, associations and other unincorporated bodies.
If your company or organisation is based in the UK, you'll have to pay Corporation Tax on all your taxable profits - wherever in the world those profits come from. The corporation tax rate is 20% on profits upto £300k. For profits above £300k, the rate is 23% but will be reduced to 21% from April 2014. If your company isn't based in the UK but operates in the UK - you'll only have to pay Corporation Tax on any taxable profits arising from your UK activities.
On completion of the incorporation process, you are legally obliged to inform HMRC when your company starts trading. The company directors are responsible for ensuring that the corporation tax liability is accurate, and your annual tax return is filed on time. You can deal directly with HMRC or you can appoint someone to deal with HMRC on your behalf for your Corporation Tax affairs.
Each year, your company is required to file a corporation tax return. From 1 April 2011, all returns must be filed online for any accounting period ending after 31st March 2010. If you submit your return late or the contents are inaccurate, you will be fined a penalty. You must pay any corporation tax that your company is liable by 9 months and 1 day after your normal due date and you must do so electronically.