"The killer app for BlackBerry is push e-mail, [but] what are the productivity benefits of always-on communications?" Mailes said.

When the pilot is complete and a business case has determined any productivity improvements, the recommendations will be circulated to government agencies, but it won't become standard issue across the public sector.

The amount spent on mobility, including the number of devices purchased, will be decided by the individual agencies which might be "hundreds or thousands," according to Mailes.

"At the moment we are asking agencies to hold off buying anything, because want to determine the business case," he said. "Then the agencies will determine how much they want to spend."

A key directive of the trial is to prevent people getting mobile devices just "because they think they need them."