MSPs from across the political spectrum will hear demands to legalise cannabis for medical use when they attend a summit on the issue in Holyrood this month.

The event’s organiser Bernadette McCreadie hopes the meeting, which will also be attended by clinicians, will put pressure on the Scottish Government to move forward with plans to allow the drug to be used by patients with conditions such as multiple sclerosis and arthritis.

Delegates at the SNP’s autumn conference last year backed the decriminalisation of cannabis for medicinal use and called on the UK Government to devolve the power to regulate the drug to the Scottish Parliament.

Cannabis is currently a Class B drug and people in possession of it can be sentenced to up to five years in prison. Dealers can face up to 14 years.

McCreadie, 40, a former auxiliary nurse, told The National she has been using cannabis for around 18 months to alleviate the painful condition she suffers from, fibromyalgia. She said using cannabis oil as a salve or tincture helped make her illness more bearable.

However, she is angry the ban means she has to buy the substance illegally - a situation she says benefits criminals and exploits the sick.

“I have to get cannabis through illegal sources. By buying it off the street you are putting money into the hands of criminals. Sick and vulnerable people are in a situation where they can be absolutely conned by dealers,” she said.

Maree Todd, for the SNP, Miles Briggs, for the Scottish Conservatives, Labour’s Anas Sarwar, the Lib Dems Alex Cole-Hamilton,and Councillor Martha Wardrop, for the Scottish Greens, are due to attend the event on 27 April.

Eleven European countries and 24 US states already allow people to use the drug to alleviate chronic pain and other symptoms.

The House of Commons all party parliamentary group on drugs reform last year recommended cannabis should be made legal in the UK for medicinal uses after it held an inquiry into its potential to help patients. Its report called on the UK Government to introduce a system that grants people access to cannabis for medical reasons and to decriminalise the growing of small amounts at home for the same purposes.

The group took evidence from more than 600 patients and medical professionals and commissioned a consultant neurologist, Prof Mike Barnes, to review published research.

His review found “good evidence” cannabis can help with chronic pain, muscle spasms often associated with multiple sclerosis and nausea and vomiting, particularly when caused as a side-effect of chemotherapy.

The inquiry heard scores of patients had sought out cannabis to relieve their symptoms but often found it impossible to get medical guidance as to how they should take the drug.

A Scottish Labour spokesman said: “We will watch the debate progress with interest”.

A Scottish Government spokesperson said: “Whilst the treatment and prevention of drug problems is devolved to the Scottish Government, the control of drugs and licensing for medical research is a reserved matter. As such, any decisions about the re-classification of cannabis for medicinal use, must currently be taken by the UK Government.”