Powers to restrict the movements of people accused of gang membership have come into force in England and Wales.
Gang injunctions can be used to ban people from certain places or from walking aggressive dogs.
The powers are similar to anti-social behaviour orders and were conceived by the former Labour government after appeals from councils for help.
Ministers say the injunctions should not replace prosecutions of gang members involved in violent crime.
Police and local councils can seek gang injunctions in the county courts against adults who they believe are involved in gang-related violence and crime.
The Labour government devised the powers after Birmingham City Council tried unsuccessfully to use ordinary civil injunctions against suspected gang members in the city.
Like Asbos, each order is tailored to the individual and could include bans from particular neighbourhoods where police know rival gangs meet to fight.
Individuals could also be forced to take part in activities designed to protect them from gang culture, such as mentoring schemes, or could be banned from wearing certain colours used by gangs to signify membership.
A separate power covering injunctions for young people aged 14 to 17 is being piloted later in the year.
'Break gang culture'
Home Office minister James Brokenshire said the government was "not expecting huge numbers" of gang injunctions to be issued, but they would be a useful tool in certain cases "to break gang culture".
"This is a very different tool than an Asbo," he said. "This is a targeted tool to deal with serious gang violence.
"This isn't anti-social behaviour - you're talking about shootings, knife incidents, serious youth violence.
"As the police have said, they should be considered as a tactical response to disrupt gang activity and we think they can be effective."
Mr Brokenshire said breaching an injunction could result in a prison sentence of up to two years or a fine.
But Paul Fletcher, who works with gangs in Sheffield, told the BBC he believed there should be more focus on preventative strategies.
"For example, getting into the schools to warn of the dangers, but also putting money into positive activities for young people at street level, so that they're steered away from the attraction of the gangs."
Isabella Sankey, from human rights group Liberty, said the injunctions would "fast-track people into the criminal justice system", not divert them away from it.
"Those people that are involved in violent, gang-related activity need to feel the full force of the law," she said.
"Those that are vulnerable to being scooped up into a gang - because their older brothers are involved, their older cousins are involved - need to have the engagement of public bodies to divert them away from such activities - not be branded criminals and face punishments in the community.
"For a government that promised to restore civil liberties, this is a very perverse position indeed."
Early intervention
But Kirk Dawes, who works as a mediator between gangs in Birmingham, said he believed the measure really could save lives.
"When we talk about diverting them away, sometimes people have to be made to do that. At the moment there is no real way of doing that.
"The injunction is something that gets in before we actually start criminalising a lot of the people who are involved in gangs."
The exact extent of gang-related crime is not clear in the UK partly because it is difficult to define a gang, when someone is a member, and the role that the groups play in specific incidents.
One 2006 study for the Home Office found that between 6% and 10% of 10 to 19-year-olds said they were in a gang.
Last year, a joint report by the prisons, police and probation watchdogs cautioned against exaggerating the power of gangs - but also warned against ignoring them.
http://www.bbc.co.uk/news/uk-12311184I'll have to read that later, but I'd be amazed if the officers were there to enforce it...
