Police have raided a suspected crime gang in the biggest operation to date to tackle dealing of party drug meow meow.
Officers arrested 12 people being investigated over the sale of £3.8 million worth of the drug through an online website, run from an industrial unit in Bolton, Greater Manchester.
All those arrested are still being held in custody, GMP said
Four men and five woman aged between 21 and 62 have been arrested on suspicion of the supply of controlled drugs and money laundering.
One man aged 48 has been arrested on suspicion of the cultivation of cannabis and two men aged 29 and 30 have been arrested on suspicion of possession with intent to supply.
They all remain in police custody after the raids yesterday at 11 addresses in Bolton, Bury, north Manchester and Salford.
Officers are investigating the sale of approximately 313 kilograms of mephedrone, with the street value of £3.8m, through the website www.wide-mouth-frogs.com.
Meow meow or Mkat is the common name for mephedrone, which until 2010 was legal to buy but not to consume as a drug.
It was made an offence to supply, or to be in possession of mephedrone, after use of the drug became increasingly widespread amongst clubbers.
Mephedrone has been linked to a number of deaths and it appears to be used as an ingredient for "legal highs" still on sale.
An Aston Martin car sits on the driveway of one of the properties raided by police
Detective superintendent Jason Hudson from Titan, the North West Regional Organised Crime Unit, said: "These strikes have taken months of planning and the operation reinforces our commitment to dismantle organised crime groups and tackle illegal drugs across our region.
"This operation is the largest of its kind in the UK since mephedrone and related substances were made illegal in 2010."
Chief superintendent David Hull from Greater Manchester Police, added: "Cracking down on drugs in our communities is a big priority for GMP and I hope today's operation shows communities we are committed to this.
"Drugs wreck lives and the crime associated with them causes misery to the whole community - so we do everything possible to find out who is responsible and put them before the courts."
Colin Tyrie, senior public health development adviser (substance misuse), for Manchester Mental Health and Social Care Trust, said: "Mephedrone, along with some of the other new synthetic drugs, appears to be overtaking cocaine and ecstasy as the 'club-drugs' or 'white powder' drugs often referred to as bubble, magic, M-cat amongst numerous other names for what are often blends of synthetic compounds produced to mimic illegal drugs like cocaine and ecstasy.
"Most users will snort these drugs or swallow them in capsules and they will often be mixed with alcohol or other drugs.
"The risks of combining drugs and alcohol are often difficult to predict and this is further complicated by the potential mix of 'blended white powders' of which many will be unknown and unpredictable in their effects."