Legal highs are so popular the only option is to "educate people who are using them" about how they can make safer choices about the drugs they take, an addiction specialist told Good Morning Britain.
Associate medical director of the CRI, David Bremner, said: "In a matter of days a new drug will be released that will have one molecule changed that then beats the law so that it is no longer illegal...all we can do is educate people who are using them on how to make safer choices."
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Seasonal rains have battered the country since late June with more than 150,000 people affected by floods and landslides.
The bus reportedly hit a tree near Russell Square.
Low pressure will throw cloud and few showers across the UK today, but it will also draw in very warm air from Europe again.