Mr. Seamus McCarthy:

The chapter on fixed penalty charges in the 2012 report stated:

The examination team reviewed summary data from the Courts Criminal Case Tracking System (CCTS) in relation to fixed charge notice cases recorded in 2011 and 2012. This indicated that for 2011 cases - which had sufficient time to be finalised in the courts - half of the cases that proceeded to summons stage were struck out in court because the related summonses had not been served. This suggests that around 11% of all recorded fixed charge notices cases end up unpaid and without being answered in court.

Obviously, there is some information available.