NETHERLANDS MOVES TO OUTLAW SUPERSTRONG 'SKUNK' CANNABIS THE sale of certain types of cannabis could be banned in the Netherlands amid concern that they have become so powerful they could have the same addictive and psychological impact as hard drugs. The Dutch Government said that it would ban the most powerful forms of cannabis, such as "skunk", after research showed that they had doubled in strength in the past few years and could now be classified as a hard drug. Levels of THC -- tetrahydrocannabinol, the psychologically active ingredient -- in skunk have almost doubled from 9 per cent in 1999 to 15 per cent now, according to the Trimbos Institute, a drug research institute that monitors cannabis sales for the Health Ministry. The rise is due to new professional growing techniques. The institute said: "It has almost doubled in strength but we don't know what the effect on public health is." Skunk has now become one of the most popular forms of cannabis on sale in the Netherlands. Between 2.5 per cent and 3 per cent of the Dutch population regularly use cannabis and there are between 30,000 and 80,000 cannabis addicts. However, it is not clear whether stronger cannabis means that more people are likely to become addicted or develop other psychological problems. The Dutch Cabinet agreed last week to commission research to determine whether skunk is as dangerous as hard drugs, and this week will lay legislation before parliament to ban its sale if it is found to be harmful. Opposition parties said that if soft drugs became illegal, authorities would lose supervision over their trade and use. The Government has agreed a series of measures to clamp down on the industry. Selling cannabis has been banned near schools and near Dutch borders with other countries, to try to stop smuggling. Police have closed half the coffee shops in Amsterdam in the past few years and ministers want to combat "cannabis tourism" by allowing cannabis to be sold only to Dutch nationals.