Former drug dealers should be recruited and trained to produce safe, legal cannabis if the UK decides to legalise marijuana, the head of an American programme overseeing the sale of the narcotic has urged.

The Commissioner in charge of legal cannabis sales in Massachusetts has said Britain should follow her state’s example of recruiting ex-drug dealers and people from communities involved in what was once the underground market for marijuana.

Ahead of talks with parliamentarians at Westminster this week, Shaleen Title, along with two other US experts on drug liberalisation, revealed that a project is under way in their state – which legalised the drug in 2016 – to retrain former cannabis dealers to enter the now legal marijuana industry.

Title’s call echoes that of Michael Semple, the EU’s one-time special representative to Afghanistan and negotiator with the Afghan Taliban, who said that a future British government would have to open “peace talks” with drug gangs if the UK goes for legalisation.

He told the Guardian he believes that government, police and other authorities must open dialogue with dealers who face going out of business.

Semple said British policymakers would not be able to ignore “the people most directly affected” by making drugs legal.

“Given the sheer number of people involved in drug dealing, and, internationally, the scale of violence associated with the ‘war on drugs’, it should not be difficult for drugs policy makers to envisage a peace process with drugs gangs.”

On the Massachusetts experiment, Title said they had recruited 150 people so far, both ex-dealers and people from areas of Boston and the wider state where drug arrests have been highest.

“They have skills already of course gleaned over a long number of years. It is a way to give people and the voters that backed legalisation in our referendum what they wanted. They did not want to hand the industry over to a few giant corporations that are going to exploit it.

“We are on our first project with 150 people and we put out a bid to vendors who can teach them how to produce cannabis that is regulated. It also includes an ownership programme to train people who were once entrepreneurs in the underground market.”

Title defended the project to absorb ex-dealers and those with drug convictions, saying: “The general model not only in Massachusetts but also in Illinois and California is to reinvest the now legal industry into those communities because it’s a fundamental issue of fairness and justice.

“If for years under drug prohibition you have this security focus on these communities then after legalisation you can hardly say to them, ‘oh never mind now, big corporations will take this business off you, they will take it from here.’ How is that fair?”

Title addressed the Lords this week along with two other American drug liberalisation experts, Sanhoo Tree, from the Washington DC based Institute for Policy Studies, and Kathryn Ledebur, the director of the Andean Information Network in South America. They argued for the need to liberalise the UK’s drugs laws as many US states are doing. New York and New Jersey are expected to be next two states to legalise cannabis use.

Tree pointed out that even the US capital, Washington, has legalised cannabis “where the sky hasn’t fallen in, where people still go to work and where kids still go to school”.

Ledebur, whose area of expertise includes programmes to allow Bolivian farmers to continue cultivating the coca plant from which cocaine is produced, said in “the shift from a US imposed violent eradication of the plant in the so-called war on drugs to a model where coca is rationed, farmers are allowed to grow it for alternatives and it actually works in creating basic farm incomes rather destroying entire crops”.

The trio were guests in London this week of the Transform Drugs Policy Foundation, which campaigns for the legalisation and regulation of drugs in the UK.