After the deadline of 31st March 2010, HMRC will review the affairs of taxpayers whose payment details they hold and who have not informed HMRC of their intention to make a disclosure.
HMRC will identify those taxpayers by:-
If HMRC find that any taxpayer has additional taxes due, and have not advised them of their plan to disclose them, they will seek higher penalties than the 10% available under the THP.
Those penalties could be up to 100% of the additional tax due and are unlikely to be less than 30%.
If a disclosure made under the THP is incomplete or inaccurate then HMRC will consider the initiation of a criminal investigation.