Photo messaging is being used by Bristol businesses to help tackle crime.
Pubs, clubs and shops in the city will alert each other to the identities of potential troublemakers using mobile technology, with 21 businesses so far signed up to the scheme.
The police say photos taken for circulation will not be kept on their database.
They will only be used to share information between premises and help identify individuals on the spot.
Pc Lawrence Billi added: "The idea is that if someone causes trouble in one place, their picture is circulated so that other businesses know not to let them in.
"The photo messages can also be sent to the police and council CCTV so that offenders can be located and dealt with.
"It's both a prevention and detection tool."