HMRC has launched a new voluntary campaign for individual taxpayers to settle their tax bills if they failed to complete a self assessment tax return up to 2011/12.
The settlement window opened this week and participants have until 15 October to complete and submit a tax return, and pay the tax and National Insurance Contributions (NICs) that they owe.
Those that come forward under this campaign will benefit from a reduced penalty of 10%.
Thereafter penalties will jump up to between 30% and 100% of the tax due, with an additional risk of criminal investigation.
In the coming weeks HMRC will also be writing directly to several thousand people it has identified using the Connect intelligence-gathering software and will follow up with calls.
HMRC said that a tax return could be required where someone had another source of income or investments for a specific year, or maybe rented out a property, which would mean that income would need to be declared to HMRC through a SA tax return.