The UK Government has had “limited success” in stopping a drugs market that costs society over £19 billion a year, according to a new report.

Dame Carol Black’s review, which released its findings on Thursday, said the main agencies responsible for halting the supply of illegal drugs have faced “budgetary constraints” in recent years.

She said it is unclear if sufficient financial backing of the National Crime Agency, the Border Force and police forces would make a difference due to the “flexibility and resilience of drug markets”.

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Kit Malthouse is chairing a UK Government drugs summit in Glasgow (Isabel Infantes/PA)

According to the report, the illicit drugs market in the UK is worth £9.4 billion a year but costs society more than double that figure.

If health considerations, the cost of crime and societal impacts are combined, the total cost of illegal drugs is £19 billion annually.

An estimated three million people took some form of drug in England and Wales last year, with 300,000 people in England using opiates or crack cocaine.

Supply of the most serious drugs – heroin and crack cocaine –  has been overtaken by the “county lines” model, in which gangs and distribution networks from cities move into smaller towns and use violence to overtake local dealers while using children or vulnerable people to sell their product.

The results come as the UK Government is holding a drugs summit in Glasgow to tackle the problem after a record level of drug-related deaths across the country.

Police and crime minister Kit Malthouse, who is chairing the conference at the SEC, said: “The findings, which we will discuss today, are troubling and paint a stark picture of how illegal drugs are devastating lives and communities, and fuelling serious violence.

“We are already taking tough action to combat county lines and violent crime and to disrupt and prosecute the organised gangs that bring so much misery.

“But clearly we all need to do more. Following this valuable review and summit we will take further action at pace, bringing together partners from across Government and beyond to address the challenges head on, based on the very best evidence and expertise.”

Health minister Jo Churchill said it was important a “holistic approach” is taken to drug addiction treatment, which also offers support for the mental health of people suffering with addiction.

“Dame Carol’s review is an essential step towards tackling drug addiction and we will build on her work to ensure victims of the illegal drug industry can access the right services,” she said.

Illegal drugs are responsible for more than a third of prisoners in UK jails, according to the report, which found the majority to be in for theft or other acquisitive crimes.

While drug treatment is seen as being good in prisons, offenders are rarely inside for long enough to complete the treatments due to relatively short sentences.

Partnered with the limited sentences, “poor hand-offs back into the community” mean prisoners are “very likely to reoffend”.

Local authorities have also reduced spending on drug treatment by 40%, because “budgets have been squeezed”.

Investment in NHS boards and charities, which are often commissioned by councils to deliver treatment programmes, have also experienced a “loss of skills, expertise and capacity”, which the report cites a “prolonged shortage of funding”, which could continue even if more cash is forthcoming.

Rob Jones, the threat leadership director at the National Crime Agency, described illegal drugs as a “corrosive threat”.

He said: “Protecting the public is our priority and we work relentlessly to tackle the whole drug supply chain.

“Our international networks and UK capabilities are uniquely placed to identify, disrupt and dismantle the transnational crime networks trafficking drugs towards and within the UK.

“Recent operations have led to the conviction of corrupt port workers moving hundreds of kilos of Class A drugs through the border, dismantling crime groups importing cocaine worth millions of pounds concealed in yachts and the seizure of 1.3 tonnes of heroin, the largest ever UK seizure.”