Scotland's top social workers yesterday called for a Royal Commission to settle the row over methadone.

The Association of Directors of Social Work (ADSW) has long argued that debate over the use of the heroin substitute had become too politicised.

The body wants an independent inquiry into both methadone policy and the wider impact of drug and alcohol abuse on Scottish children and families. The call came in a five-point ADSW "manifesto" launched ahead of a Scottish Parliament election campaign which is almost certain to see major party political divisions on addiction and how it is treated.

David Crawford, the body's president, said: "ADSW has called previously for a depoliticised debate on these issues. Each party should consider a Royal Commission. The seriousness of the issue merits the response."

Mr Crawford, whose runs the social work department at Renfrewshire Council, was speaking at a conference on social work organised by Holyrood Events in Edinburgh.

He said: "The significant rise in the number of children with substance misusing parents is one of the most worrying developments Scottish society faces today.

"It has put increased pressure on children's social work services and shows no signs of abating. In addition, there is major controversy over the effectiveness of methadone-based treatment.

"Scotland needs a non-politicised debate to ensure that the issues and all possible solutions are fully investigated."

The ADSW calls were backed by the SNP, which has previously argued for an independent commission to investigate the issue.

Stewart Stevenson, the party's deputy justice spokesman, said: "Scotland's drug problem is far too serious to be opportunistically politicised by policy makers.

"What Scotland is desperately lacking is advanced research in the area and robust information on drugs, such as the root causes of drug addiction. A long-term sustainable drugs strategy can only be attained through extensive knowledge and understanding of the problem as a whole."

Concerns over methadone have been championed by Tory leader Annabel Goldie.

The Conservatives will campaign hard on the next election with a pledge of an extra £100m a year for rehab programmes, including cold-turkey treatments.

Miss Goldie, however, was far from impressed by the ADSW proposal.

She said: "Scotland does not need a Royal Commission. It needs action. We have listened to the addicts and they want treatment, including more abstinence-based programmes."

Mr Crawford yesterday also outlined four other key commitments the ADSW would like to see from whoever wins the next election.

The body said it wanted to see parties recommit to the principles of the children's hearing system; address funding issues; simplify and reinvigorate the range of community sentences; and streamline social work regulation.