POLITICIANS have questioned Police Scotland's use of stop search following new research that warns the tactic might infringe human rights and could lead to public disorder.

A report by Edinburgh University found stop search increased by more than 300% in many areas of Scotland between 2005 and 2010.

Academic Kath Murray found the tactic was legally questionable, "unenforceable" and that Scots were four times more likely to be stop searched than people south of the Border.

Last night Labour's justice spokesman Graeme Pearson said Police Scotland and the Justice Secretary needed to answer key questions as a result of the research findings. He also questioned the timing of a press conference on Wednesday pointing out the benefits of stop search.

He said: "Where is the policing by consent delivered? How is democratic accountability delivered in these circumstances? And who authorised and approved this huge rise in stop and search?

"The Cabinet Secretary should not hide behind the façade that these things are operational decisions."

Earlier this week, Justice Secretary Kenny MacAskill and Police Scotland praised stop-searches for helping to produce a massive drop in violent crime and released new figures showing more than 500,000 people had been stop searched in the past nine months, a 0.2% fall on the previous year.

Police Scotland assistant chief constable Wayne Mawson said: "The use of stop and search... used in the right place at the right time, is an effective and legal tactic."

A Scottish Government spokeswoman said: "Stop and search, in the right circumstances, can help reduce crime. Police Scotland's statistics published this week suggest this approach is working."