Scotch whisky has become liquid gold as speculators pour into the drinks market.

Collectable single malts have risen by almost 175% in value in five years, outpacing bullion, new figures reveal. Among the most valuable brands the rate of return can be more than treble.

Magnates from the Far East, oligarchs from Russia, and billionaires from the US have joined in the dash to cash in on the boom.

Quarterly auctions in Edinburgh are regularly reaching six figures, with single bottles chasing hands for up to £46,000.

Andy Simpson, head of Whisky Highland, who advise investors, appraise collections, and provide industry research to the major manufacturers, said: "Between the end of 2008 and the end of November 2013 the top performing 1000 bottles - the Whisky Highland Investment Grade Scotch 1000 Index - has increased by 173.38%."

Mr Simpson, based in Tain, Rosshire, added: "Global demand has been steadily increasing."