Low value crimes such as pickpocketing are the most common crimes to occur on most rail networks. Limited police resources mean that they often go un-investigated. The new system will go some way to rectifying this situation.

"It takes just a few seconds to tell the passenger tracking software about each pick-pocketing incident. The tracking software then automatically correlates similar incidents. Once certain thresholds are met, the software notifies transit police by presenting photographs of individuals who are believed to be likely pick-pockets.

Human surveillance resources can then be directed to these suspects when the suspects are next detected entering the rail network," he says.

Haddy says the correlation capabilities of the technology show considerable potential and there are more possibilities to explore or to further advance in this area in future.

Admittedly, the software relies on a train network being complex and, ideally, having a ticketing system that registers entry and exit movements through its turnstile infrastructure. This makes it ideal for cities such as London, Seoul and Hong Kong.