Police in other forces are also believed to use overt surveillance
More than 900 people have been followed and filmed by Greater Manchester Police as part of a pilot project to prevent crime, the BBC has learned.
Footage of the suspected criminals in Trafford has been collected since 2006 and their images added to a database.
But they do not have to have committed a crime and anyone simply associating with offenders can be targeted.
The pilot scheme is designed to build intelligence and act as a deterrent to active criminals, the force said.
The Trafford division's video intelligence unit was set up by two police officers in 2006 to keep track of offenders.
It involves the officers openly using hand-held cameras as they follow suspects on the street.
As part of the project, prisoners released on licence are sent letters saying that footage of them could be placed on the video sharing website, YouTube.
This would allow police to upload footage of the criminal to the site if he went missing and officers wanted to trace him.
But as well as known offenders, other criteria for an individual being filmed in the street includes:
- Intelligence suggests they are associating with prolific offenders
- They have been stopped in an area of high crime under suspicious circumstances
- They are suspected of committing criminal offences or causing anti-social behaviour
Greater Manchester Police (GMP) said the tactic was a good way of discouraging prolific offenders and was based on police intelligence on suspected criminals.
Supt Shirley Wilding, of GMP's Trafford Division, said: "It's not innocent members of the public who are doing nothing that get filmed, it's people that are either associating with, or suspected to be involved, in crime.
"Since footage was first uploaded to YouTube in December 2008, several offenders have been arrested and successfully recalled to prison after breaching licence conditions.
"Overt surveillance also allows officers to gain more up-to-date information on offenders and their associates and this prevents them having to rely on a name or a description that could be dated."
Since the pilot began in 2006, crime in Trafford has fallen from 23,721 incidents in 2006/07 to 17,622 incidents last year.
But GMP said it was difficult to say with any certainty what impact the video unit has had on the figures.
Kieran Walsh, a Manchester-based civil liberties lawyer, said the pilot could have implications for the force under Article Eight of the European Convention on Human Rights.
Mr Walsh, of Tuckers Solicitors, said officers would need to establish the filming was a "proportionate and reasonable" response to a crime problem they faced in the area.
"If you are targeted in an individual investigation then there is a specific reason for taking that image," he said.
"In this case it looks like these individuals are not suspected of any particular crime - it's what they might do in the future."
Mr Walsh said the force also needed to have established a procedure for what happens to the images after they are collected, and how long they are held.
The length of time the footage will be kept is subject to an internal review, but GMP said it was anticipated to be five years.