THE true scale of Scotland's unemployment was today put at 503,000 by the Scottish Trades Union Congress, more than double the most recent official figure.

Ahead of the quarterly jobless numbers from the Office for National Statistics (ONS) today, which are again expected to show a rise, the STUC released its estimate of what it called "Scotland's full-time employment deficit".

While the ONS figure for the latest quarter, August to October, put Scotland's unemployment rate at 229,000 or 8.5%, the STUC calculated what it believes is a more accurate rate – taking into account not just the official unemployed but also those deemed economically inactive and others described as "underemployed" – at 502,655 or 18.6%.

Grahame Smith, the STUC general secretary, said his organisation's estimates were "stunning", stressing: "There are simply far too many people in Scotland at this time unable to access the quality, full-time work opportunities necessary to provide for a decent standard of living for themselves and their families."

He said the STUC was frustrated by the complacency of many politicians on the current state of the labour market.

"The focus only on headline figures serves to obscure some of the most worrying labour market trends," he said.

Insisting the STUC's estimate was "robust", Mr Smith added: "Of course, the UK Government is continuing down the road of austerity, cutting jobs when they are most needed."

A Scottish Government spokesman said: "We still have a situation of higher employment in Scotland compared to the UK as a whole, lower economic inactivity rates, and a lower unemployment rate compared to most of the other nations and regions of the UK, but we are clear that more needs to be done.

"That is why we are calling on the UK Government to take real action to strengthen recovery, and for a UK-wide jobs summit to agree an immediate programme of employment creation."

Analysts expect today's data to show a rise from last month's UK figure of 2.6 million amid predictions the jobless total will not fall below 2.5 million until 2016 at the earliest and will hit 2.9 million next year.

The Federation of Small Businesses said smaller firms would be looking to shed staff in the first three months of this year.

Meanwhile, there was a glimmer of positive economic news yesterday when the latest inflation figure fell from 4.8% in November to 4.2% in December, helped by falls in clothing, fuel and alcohol prices.