The Garda has been overstating the number of sex crimes reported to it by as much as 26 per cent in some years, new figures show.

There had been concern for decades that only a small percentage of sex crime victims ever made a complaint to the Garda. But new statistics show the true rate of reporting is even lower than previously believed.

The errors were found during an examination of the Garda’s crime-counting practices since errors in homicide statistics came to light last year.

Last month, the Central Statistics Office (CSO) revealed the number of homicides since 2003 had been underestimated by 18 per cent.

The Rape Crisis Centre said it was concerned at the figures and was especially worried that fewer victims of sexual offending had come forward than previously believed

The Irish Times has obtained new figures – compiled by the CSO in conjunction with the Garda – for other crime types which were examined and revised at the same time as the homicide data.

Revisions negligible

In most of the different categories, the revisions made were negligible. But in the area of sex offending, the errors were much more pronounced.

The Garda overestimated the number of sex crimes reported in 12 of the 14 years under review. Photograph: Frank Miller

For example, the Garda’s figure for sexual offences reported in 2003 was 1,986. The revised figure is 1,573, meaning the number of victims who came forward that year is 26 per cent lower than previously stated.

The Rape Crisis Centre said it was concerned at the figures and was especially worried that fewer victims of sexual offending had come forward than previously believed.

The CSO said part of the reason for the over-recording of crimes was because until now, if repeated crimes were committed by a person on the same victim, each incident was recorded as a separate case. During the 14-year period under review, from 2003 to 2016, sex crime reporting was overestimated by the Garda by 6 per cent overall.

The Garda overestimated the number of sex crimes reported in 12 of the 14 years under review.