Many regional forces (on both sides of the pond) are seeing the value of body-worn cameras; and the commitment from Greater Manchester Police is one of the largest since London's Metropolitan Police began rolling out over 20,000 devices to officers last year. While body cams offer several obvious benefits to both the police and the public, they have their downsides.

Preliminary results from an ongoing study of UK and US forces have shown officers are 15 percent more likely to be assaulted when wearing a camera (idiocy knows no bounds, it seems). And when officers are given more freedom to switch cameras on and off as they feel necessary, use of force increases significantly compared with camera-free shifts, suggesting we still have plenty to learn about where, when and how body cams should be used.