A drop in crime reports over the last four years does not only reflect a decrease in offences but a recent tendency to ignore petty wrongdoings, according to a leading criminologist.

Figures released in Parliament showed the number of crime reports dropped by almost 5,000 in the last four years.

A Justice Ministry spokesman said: "This is mainly due to a more efficient system, where criminals who commit multiple crimes are quickly removed from the streets".

This resulted in a rise in the number of arraignments, convictions and inmates. In fact, the number of prisoners has reached a record amount after rising by more than a third over the last four years.

"Most of those 5,000 crimes were committed by the same criminals, especially those addicted to drugs, who repeatedly steal to sustain their habit," the spokesman said.

Criminologist Saviour Formosa believes the drop in reports also reflects society's perception of what is worth reporting and its trust in the authorities.

Dr Formosa said that according to an international scientific analysis every country went through a reporting cycle. "Those who report crime, do so for peace of mind, because they trust the authority responsible, must do so to claim insurance and may have any stolen items returned.

"On the other hand, others do not because they think the crime is petty, they fear revenge by those they report, repercussions on their family and friends, doubt whether the case can be solved and do not trust the system," he added.

Other factors, he said, also contributed to the drop in reports, including better enforcement, a stronger police presence, the introduction of security guards in car parks and the installation of surveillance cameras and lighting in the streets.

However, predicting whether the trend would continue was easier said than done because crime depended on social and economic conditions and results could vary drastically, he said.

"Crime, especially the serious ones, is expected to increase during an economic slowdown. On the other hand, when considering that reporting is directly related to perception, a change in tendency is hard to come by and the current trend may be sustained."