Conservative drug reformers and leading psychiatrists want ministers to reclassify the compound so that it can be explored as a medicine.

The same demand is being made by people suffering from cluster headaches, which involve severe pain that existing drugs do little to relieve, amid evidence that the drug psilocybin can help reduce both the condition's physical and mental impact.

The most tightly controlled drug under the Misuse of Drugs Act is the active ingredient in magic mushrooms. It should be scheduled for two to facilitate more studies into its effectiveness as a treatment for cluster headaches.

Three psychiatrists have written to Sajid Javid, the health secretary, and Kit Malthouse, the crime and policing minister, urging them to rethink.

Prof Allan Young, Prof Karl Friston and Prof Simon Wessely want the ministers to commission Sir Chris Whitty, the chief medical officer for England, to assess the evidence for the harms and utility of psilocybin with a view to rescheduling this promising medicine.

Wessely was commissioned by Theresa May to lead an independent review into the Mental Health Act.

The results of a recent study show that the drug can help reduce the symptoms of treatment-resistant depression. They say that the compound is being investigated for its potential benefits for people with eating disorders, as well as alcohol, cocaine, and tobacco addiction.

There has been no recent review of the evidence for the current scheduling.

They argue that the Home Office's refusal to change the compound is contrary to the precedent set by cannabis-based products.

Ainslie Course, a director of the charity ClusterBusters UK, and 160 other people with cluster headaches have written to Javid and Malthouse in order to get a relaxation.

The brutality and severity of the pain wreaks havoc on relationships, family life, employment and friends. She writes that our condition has a suicide rate 20 times the national average. She says that most sufferers are breaking the law by buying the drug online.

The Conservative Drug Policy Reform Group includes an ex-justice minister.

In order to allow research into them in a meeting with Boris Johnson, he agreed to change the substances he used. In the 10 months since, nothing has changed.

Cluster headaches sufferers hold guns to their heads as they weather attacks. Those who know about it know the pain that comes with it.

To keep in place the red tape that precludes further clinical knowledge of how this pain can be alleviated with psilocybin is to cement thousands in the UK between a rock and a hard place. Do they break the law to access a medicine that seems to work, or do they accept that the Home Office has consigned them to a life of suffering more preventable attacks?

The government sympathizes with people who suffer from cluster headaches.

Medicines with controlled drugs must go through a licensing process to ensure their safety. The Medicines and healthcare products Regulatory Agency has yet to approve a medicine based on the drug.

We are working with the Advisory Council on the Misuse of Drugs to consider whether barriers to legitimate research on controlled drugs could be removed.