Gangs from London are increasingly "spreading their wings" to seek markets for drugs in other parts of the country, a Metropolitan Police officer has warned.
Officers believe as many as 54 of the capital's most dangerous gangs have "tentacles" in other towns and cities, operating in a similar way to business franchises, the BBC has reported.
The warning came a day after co-ordinated raids in the Thames Valley, Edinburgh, Essex, Bedfordshire and London in which 29 people were arrested in an operation targeting the south London-based GAS gang.
But the senior officer who speaks on gangs for the Association of Chief Police Officers said "significant headway" was being made in dealing with gang-related crime, with a decrease in gun and knife crime.
Deputy Chief Constable David Thompson of West Midlands Police told BBC Radio 4's Today programme that gangs had always relocated in search of opportunities to make money or in response to pressure from police on their home turf. He rejected suggestions that the situation in the UK could be compared with the problems experienced in the US.
Following yesterday's raids, Detective Chief Inspector Tim Champion, from the Met's Operation Trident gang crime command, told the Today programme: "What we are noticing is that gangs are spreading their wings, so rather than working in London, they are going into the counties, and even Scotland, to deal drugs. So basically it's an expanding trade.
"We have communication with all our colleagues in the county forces and in Scotland, so distance is an issue if you are actually talking about operations from a London perspective, but we work with local forces up there. So it's not always the case we have to go up there ourselves."
Mr Thompson told Today that organised criminals have "never really recognised boundaries".
"In my time in policing I have seen gangs relocate," he said. "Sometimes it's for chaotic reasons such as family reasons, but of course sometimes people will follow opportunities to increase opportunity for drug dealing, and of course if there's police enforcement in an area, they might think twice about relocating.
"There are occasional reasons why criminals will move into different areas. Of course, people trying to access firearms and drugs will work beyond police force boundaries. But you have to recognise that we are all creatures of habit, so relocating off into a new neighbourhood or new area is actually quite risky and quite difficult for a criminal to operate.
"I don't think there's anything new particularly about what's being discussed. I think there are some particular pressures being brought to bear in the capital and I think what's good about the operation we heard about is the Met taking that enforcement lead on the gang that they know about that's working beyond their boundaries."
Mr Thompson said police had made progress in operations to deal with organised gang crime over recent years.
"I wouldn't minimise that there are still clearly risks around gun and knife crime we want to work harder on," he said.
"But if you think back over the last 10 years, with the headlines about young people being victims of gun and knife crime, those issues still happen but I think actually there's a significant success so far.
"Here in the West Midlands I think we've seen some good evidence on the gangs we've got that the traditional structures we might have seen many years ago have broken down. We've become far more focused on mapping and understanding gangs and organised crime groups, so as a result of the police knowing more we can often count and identify more gang members.
"I think it's difficult to say but my sense is the harm and the visibility of gangs has significantly reduced as a result of a lot of work. Gun and knife crime is going down.
"I do think we are making significant headway and the sense that there's a growing swathe of drugs markets, I don't think that is the case.
"I think we are understanding the phenomenon better, I think we are doing some extremely good work and you can't really compare the challenges we face against the problems in the States. There are gangs that are identified but we've got to be careful sometimes of implying a level of organisation around what are often quite chaotic groups of young people."