The First Minister was accused by the SNP yesterday of running scared of open debate with Alex Salmond, during First Minister's Questions at Holyrood, which were dominated by the executive's handling of the problem of drugs.

The First Minister was accused by the SNP yesterday of running scared of open debate with Alex Salmond.

The accusation from SNP deputy leader Nicol Sturgeon came during First Minister's Questions at Holyrood, which were dominated by the executive's handling of the problem of drugs.

The nationalists claimed that Jack McConnell was presiding over lengthening waiting times for those seeking help with addiction, while the Conservatives claimed their proposal to put £100m more into rehabilitation would save 10 times that figure in the long-term cost to society.

When Mr McConnell sought to turn questions round to the SNP's economic policies, Ms Sturgeon said: "The First Minister has had two opportunities in the last week to debate live on TV with the SNP, to pitch his policies against ours. On both those occasions, he has ducked the opportunity.

"This is First Minister's Questions - the opportunity for him to answer questions about his record, not repeat untruths about the SNP that he doesn't have the courage to back up in debate."

Last night, it emerged that a major debate organised by Edinburgh Chamber of Commerce at the Edinburgh International Conference Centre on February 1 had been cancelled because after considering the invitation for two months, Mr McConnell turned it down yesterday, offering to send the Labour back bencher Wendy Alexander.

A chamber spokesman said: "We are not politically aligned, but everyone would like to see the two people contending to be First Minister in debate.

"The situation is that Alex Salmond agreed very early on to engage in the debate and our preference was for the First Minister. Today, we were offered Wendy Alexander but that has come too late for February 1, so we will try again for Mr McConnell on March 1."

Labour has fielded Scottish Secretary Douglas Alexander against Mr Salmond recently on the Newsnight television programme and on BBC Radio 4's Today.

In an interview this morning on GMTV, the SNP leader is expected to say: "It is now incumbent on the First Minister that he comes into the ring and lets people judge.

"In Scotland we've had a great wealth of experience and tradition of the debates.

"I really do think it's time for the First Minister to step into the ring to make his case. I'll be waiting for him and then the people can judge who can best take Scotland forward."

Angus Robertson, the SNP's election campaign director, said: "Labour's tactic appears to be to keep the First Minister out of this, but it's a high-risk strategy because people are beginning to notice.

"It is almost universal that in a democracy there are debates between the contenders for the highest office. The longer Labour holds off, the more suspicious it looks.

"They can't go on about falling turnout and the disconnection between politicians and the electorate and then refuse to take part in debate."

A Labour spokesman said: "Jack McConnell is the First Minister of Scotland with an important job to do in improving schools, hospitals and our economy. Alex Salmond is a candidate trying to get elected to the Scottish Parliament. Alex Salmond clearly has time on his hands and wants publicity."

It emerged during Holyrood questions yesterday that a special cabinet sub-committee on environmental sustainability had not met since June and would not convene again until the spring.

Robin Harper, co-convener of the Greens, said: "It seems to me from this that climate change and sustainability has slipped off your agenda," but the First Minister insisted that taking action did not depend on committee meetings.