Company accounts, as well as tax form CT600 and the tax computations will all have to be filed online using the ‘inline extensible business reporting language’ (iXBRL) standard from 2011.

Compulsory filing will apply to all returns delivered after 31 March 2011, for accounting periods ending after 31 March 2010.

The change will affect anyone who is not using software which can deal with iXBRL although HMRC will provide basic software, many businesses will find that they will have to enter their accounts figures twice or pay an adviser to do this for them.

The Institute of Chartered Accountants suggests that companies may postpone the changes for a year: by filing a tax return early. So if you are filing a return for the year ending April 2010, if you file it before 1 April 2011 you can still use the paper format.