Thousands of ecstasy tablets have been seized

The number of 11 to 15-year-olds involved was five times higher than the number of people aged 51 to 55.

The force's drugs co-ordinator, Chief Superintendent Barry Dougall, said: "The initial findings underline once again the very great need for everyone to divert young people away from the obvious dangers associated with drugs.

"It is evident from the figures and the cases we have gathered that teenagers, some still at school, are involved.

"For their sakes, and for the sake of everyone in our communities, there will be no let up in the enforcement or education processes which are the backbone of the Know The Score campaign."

All eight Scottish police forces are taking part in the crackdown, which has seen the seizure of drugs with an estimated street value totalling �3.7m.

Jim Orr: "Significant seizures"

The forces charged 847 people with dealing drugs, while 3,490 people were charged with possession.

The seizures included 8.8kg of heroin worth �1.23m, 300kg of cannabis valued at �1.5m, and 62,457 ecstasy tablets with a street value of �1.5m.

Jim Orr, director of the Scottish Drug Enforcement Agency, said: "The information that we are building up on dealers is resulting in significant seizures on virtually a daily basis.

"This is good news for the police and our morale is high as we see the impact of our efforts grow.

"But it is also good news for the public and I would urge them to keep feeding information to us."