A plan by Halifax Regional Police to buy portable wireless security cameras would be of questionable benefit, says an expert on the use of surveillance cameras.

Police already have surveillance cameras, but expect to receive the portable ones in a few weeks, just in time for two big concerts on the Halifax Common.

When Paul McCartney and Kiss perform there during July shows, police will be keeping an eye on everything but the stage.

Major outdoor events like the concerts will be a proving ground for their new portable cameras. But crowd control is only one reason police want the new cameras.

They also want to use them in high crime areas, and that is what Prof. Randy Lippert questions.

Lippert is a criminology professor at the University of Windsor. He said cameras have not helped deter crime in major cities like London, England, where they are in wide use.

"Most of the activities that people fear the most — that is, you know, bombings and beatings — aren't deterred by the presence of the cameras, and they do tend to have a displacement effect, which means the activity that you are trying to prevent just moves to another space," Lippert said.

Lippert helped write a Canadian study on crime and cameras in public places. He said the invasion of privacy is a hefty price to pay for questionable security benefits.

"The onus on any police service would be to prove the cameras would have a substantial effect on deterring crime before they put them in, and I think that would be difficult to do," he said.