Dr. Karina Doorley:

The system could be designed to be revenue neutral. As regards the policy change implemented in the early 2000s, there was lots of money to spend at the time. The situation of one-earner couples did not change in nominal terms. They did not lose anything; their situation was exactly the same. The tax bill on two-earner couples and singles, however, went down. In a scenario where Exchequer funds were available to pay for that, that would be the way to do it because it does not penalise anybody. Otherwise, switching to individual taxation for one-earner couples will have a financial impact on them because the secondary earner will no longer be able to share part of his or her standard rate band with the primary earner.