I am advised by Revenue that an unfortunate mistake was made in this case. Revenue has now taken steps to rectify the matter and to apologise to the taxpayer. In May 2011 the taxpayer informed them that she was in receipt of widow's pension from the Department of Social Protection since 2006. As a result, an adjustment of her tax credits was needed, to remove the married person's tax credit to which she was no longer entitled, and to replace it with credits appropriate to her new status.
Unfortunately, only the first part of this process was carried out, and the result was an apparent underpayment of tax for the years 2007 to 2010. A statement of underpayment was issued in early August. Revenue has now however corrected the situation by adding the credits to which she is entitled, and the result is that no additional tax is due.
Revenue deeply regret the distress caused to the taxpayer by the erroneous assessment of her tax liability, and have written directly to apologise.