Typically the first returns subject to the new rules will be as follows:
VAT - Returns for 3 months to March 2009;
Corporation tax - Returns for accounting periods starting on or after 1 April 2008;
Income tax and CGT - Tax year ending 5 April 2009.
Previous posts on this blog that have also addressed the new penalties regime include: The new penalties regime - making tax taxing; and 'Take care to avoid a penalty'