More than one in 10 people in Scotland is underemployed, twice as many as five years ago, according to analysis by a former Bank of England economist.

The paper for think-tank the National Institute of Economic and Social Research said more than 10% of the population were unable to work enough hours.

Labour said the figures revealed the untold story of a jobs "crisis". But the Tory-LibDem Coalition hit back, saying four out of five people chose to work part-time because it suited them.

The paper's authors, former member of the Bank of England's monetary policy committee David Blanchflower and Prof David Bell from Stirling University, warn that their analysis deals "quite a big blow" to the Coalition's claims.

"People want to work" they add, but are struggling to find jobs that give them enough hours a week.

Their paper shows that across the UK the percentage of those classified as "underemployed" rose from 6.2% of the workforce in 2008 to 9.9% in 2012. But in Scotland the figure rose from 4.9% to 10.2%.

A Department for Work and Pensions spokesman said: "Part-time working suits millions of people."