Reformed criminals and convicted drug users who have recovered from their addiction should be allowed to become magistrates, according to a centre-right thinktank.

The magistracy, which is overwhelming white, middle-class and elderly, could be transformed if the experience of past offenders is put to legal use, Policy Exchange argues.

It says reformed offenders should be encouraged to become magistrates and positive role models in the new drug and sobriety courts. A full report on the impact of recruitment changes is due to be published by the thinktank next year.

Magistrates courts deal with 90% of criminal cases. More than half of JPs are aged over 60 and fewer than 4% are under the age of 40.

The thinktank believes that ex-offenders would be well-suited to preside over the type of complex issues faced by those with addictions and mental health problems. It says there should be an expansion in the number of specialised courts in England and Wales that work with low-level, non-violent offenders to tackle problems such as drug addiction, alcoholism and mental health.

Offenders dealt with at these courts are required to return on a regular basis, often weekly, to report on their progress, submit urine tests and demonstrate their compliance with court orders. They can be sent to prison for failure to comply with the terms of their order.

Policy Exchange will recommend recruitment rules be changed so that if an offender has been crime-free for a minimum period of five years and has paid back to their community through volunteering work and other public service, they would be allowed and encouraged to apply to be a lay magistrate.

It also proposes that there should be a maximum time limit of 10 years on the bench, rather than magistrates serving until the age of 70 by default. It says this would encourage greater turnover of magistrates, provide younger people with more opportunity to volunteer to take on the roles and inject greater innovation and dynamism into the courts system.

Max Chambers, head of crime and justice at Policy Exchange, said: "Even though money is tight, we want to see more courts adopting this innovative approach to dealing with crime. Tackling offenders' issues in court and holding them accountable for their progress is about moving from assembly-line justice to problem-solving justice.

"We need to open this system up to those with first-hand experience of what addiction and the criminal justice system are really like. Who better to help turn offenders' lives around and make our streets safer than someone who's been through it, come out the other side and is now making a positive contribution to society?"

One prominent supporter of the proposal is the Friends actor Matthew Perry, who is in London this week to promote drug courts. He said: "The Obama administration is investing heavily in these court models in the United States because they are proven to work, and we are increasingly seeing the use of former addicts as magistrates and judges in helping to turn people's lives around. It's simple – drug courts and sobriety courts save lives and taxpayer dollars, and that's why I'm so committed to seeing more of them get off the ground."

A Ministry of Justice spokesperson said: "A criminal conviction does not automatically disqualify someone from being appointed as a magistrate, nor does a previous addiction to drugs or alcohol, but the public has a right to expect that magistrates will be people of integrity and good character. For that very important reason, it will remain the case that anyone in whom the public is unlikely to have confidence will not be appointed to the magistracy."