Justice Secretary Kenny MacAskill announced yesterday that 16 new scanners will be issued: Strathclyde Police will be given seven, Lothian and Borders will get two and the rest will be dispersed among the other forces including the British Transport Police.

The machines, which cost a total of £90,000, are single poles that take less than a minute to set up and are able to detect knives through a 360-degree radius.

Mr MacAskill said he wanted police to be armed with the equipment they needed to make communities safer.

“The investment of these new metal detectors will help them do just that,” he added.

However, Labour’s justice spokesman Richard Baker claimed if Mr MacAskill wanted to stop knife crime he had to back Labour’s plans for minimum mandatory sentences.

He said: “These plans, along with tough policing, will reap rewards in persuading knife thugs to change their ways.”

Mr MacAskill made the announcement in Inverness yesterday at the SNP’s annual conference, where he was given a standing ovation at the start and at the end of his speech.

He told delegates that many Labour politicians privately supported his decision to release the man convicted of the Lockerbie bombing, Abdelbaset Ali Mohmed al Megrahi.

He said Prime Minister Gordon Brown “couldn’t decide whether he was for it or against”, and Labour’s Holyrood leader Iain Gray “opposed my decision but only after I had taken it”.

But he added: “Many Labour MPs and MSPs have since told me that they agreed with my decision but none of them have spoken out. Only Malcolm Chisholm had the courage of his convictions.”

However, Mr Baker insisted most Scots believed the decision to return Megrahi to Libya was wrong.

He said he was “personally sickened to see Kenny MacAskill grandstanding to the SNP conference about releasing the Lockerbie bomber”.

Also at the SNP conference, Finance Secretary John Swinney urged Chancellor Alistair Darling to accelerate more capital spending to “protect the livelihoods of the people of our country”.

He told delegates there was a “compelling case” for Mr Darling, in his pre-Budget report next month, to help economic recovery by “further accelerating” capital budgets into 2010-11 to support thousands of jobs across Scotland.

He said: “For every £100m in extra capital spending, we can safeguard 1500 jobs in our country.”

The money would enable more investment in housing, transport and other infrastructure projects “essential to the safeguarding of jobs and to recovery”, he said.

The only new announcement in Mr Swinney’’s speech was a pledge to extend water rates relief for small charities until 2015. He also defended his decision to scrap the Glasgow Airport Rail Link (Garl).

He said: “I know that decision has disappointed some people. But we have to be able to put the public finances on a stable footing for the years to come.”

The scrapping of Garl was announced by Mr Swinney in his draft budget speech and he warned opposition parties not to “play games” with the budget.

The warning follows opposition challenges to this year’s budget. The plans of the minority SNP administration were only passed at the second attempt. Mr Swinney told delegates the Holyrood opposition “thought there was a way to attack the budget and not face up to their responsibilities”.

He said: “A week after voting against the budget the opposition were back, but this time they were voting for the budget.

“They found out the hard way that you can’t play games with the public services of Scotland.

“And I hope these lessons are to the fore in the thinking of opposition parties in forming next year’s budget.”