Kush is a cheap and deadly drug that has swept through at least six West African countries in recent years.

Sierra Leone’s President Julius Maada Bio last April called for a crackdown on it, describing the drug as an “epidemic” and a “national threat”.

He launched a task force on drug and substance abuse, promising to lead a government approach focused on prevention and treatment involving law enforcement and community engagement.

But the lack of information about the chemicals it contained and their origins have complicated efforts to combat it.

Now, tests conducted by the Global Initiative against Transnational Organized Crime at the request of his government have identified the core chemical components of kush.

In a report published on Tuesday, the group said it had found that more than half of samples contain nitazenes, a highly addictive and deadly synthetic opioid which is up to 25 per cent more potent than fentanyl.

The other half contained synthetic cannabinoids.

It also revealed that some of these ingredients are imported from abroad, including from China, the Netherlands, and likely the United Kingdom.

Once in Sierra Leone, they are then combined in labs in the capital, Freetown, and the resulting liquid is sprayed onto plant material intended to be smoked and sold as kush.

As it has soared in popularity, so has deaths associated with it and local corruption, with smoking bars sometimes popping up within metres of police stations.