New approach needed to 'legal highs'
25 August 2013 Last updated at 09:34 BST
A former government drugs advisor has told the BBC that a new approach is needed towards so-called legal highs.
Two major festivals taking place this weekend have banned the sale of the substances.
Professor David Nutt says he wants to see a system similar to the one in the Netherlands where people can get the drugs tested without fear of prosecution.
Jane-Frances Kelly reports.