The Budget changes to corporation tax rates and allowances, which included reducing the main rate of corporation tax from 28% to 26% and the small profits rate from 21% to 20%, will take effect from the date the Finance Bill 2011 receives royal assent.
They will only affect returns with accounting periods that end on or after 1 April 2011 with filing dates of 1 April 2012 or later.
Companies with no tax liability will not be affected, so can file their company tax return early, if they wish to. If a company does have a tax liability, it will need to wait until the online service is updated in October 2011 to file its return using the new rates.
Companies that will to file their return before then, should contact their tax office for further advice.