You need to complete CT600I Tax Return Form for Supplementary charge in respect of ring fence trades section if for any period beginning (or deemed to have begun) on or after 17 April 2002 the company carried on a ring fence trade. You must complete these supplementary pages and form CT600.
A ring fence trade is defined at S502 and S492 ICTA 1988 and covers oil extraction activities and, or, the acquisition, enjoyment or exploitation of oil rights in the UK or a designated area. In practice this means all such onshore and offshore activities, to the outer edge of the UK Continental Shelf.
The supplementary charge is applied to all adjusted ring fence profits arising on or after 17 April 2002.
You need to enter the figure of ring fence profit or loss of the accounting period, after any group relief surrendered to the company and set against ring fence profits of the period, but before losses brought forward or carried back from other periods.
To arrive at the adjusted ring fence profits the financing costs within the ring fence profits or losses are left out of the account. Financing costs are the costs of debt finance, and include:
HMRC have provided following Company tax return guide to form CT600 (2020) Version 3 for accounting periods starting on or after 1 April 2015 to assist Companies complete the Corporation tax returns. Further information can also be found on GOV.UK website.