More than �25m of cannabis was seized last year

The haul included heroin, cocaine and ecstasy, worth more than �22.3m, and cannabis valued at �25.4m.

The SDEA annual report said seizures of class A drugs had risen from 357kg in 2004/05 to 383kg in 2005/06.

However, the agency failed to meet its target for the confiscation of criminal assets for the second year in a row.

More than �5.8m in criminal assets were referred to Scotland's prosecutors for consideration under the Proceeds of Crime Act during that time, compared to a target of �8.5m.

The previous year �12m worth of assets were reported to the Crown Office, when the target was �22m.

'Hostile environment'

Graeme Pearson, the agency's director, said it took time to gather evidence to prove that assets had been illegally obtained.

He described the overall results as impressive and said the agency would continue to make life difficult for criminal groups operating in Scotland.

"Serious organised crime groups continue to pose the single biggest threat to the stability and prosperity of Scotland's communities," he added.

"We have worked hard to ensure that Scotland is not a soft target and we will continue our efforts to create an increasingly hostile environment for organised crime."