Job insecurity and short hours contract are blighting the lives of many workers, say trade unionists.

The Trades Union Congress (TUC) has published new analysis of a Labour Force Survey of the fourth quarter of last year which shows that on top of 700,000 workers who report being on zero-hours contracts, a further 820,000 say they are underemployed on between 0 and 19 hours a week.

The analysis shows that average hourly wages for those working short hours or underemployed is £8.40, compared to an average for all employees of £13.20.

The TUC says that while zero-hours contracts have dominated the media headlines, short hours-contracts, along with other forms of insecure work, are also blighting the lives of many workers.

The TUC says that short-hours contracts, which can guarantee as little as one hour a week, can allow employers to get out of paying national insurance contributions.

The average underemployed short-hours worker would have to work more than 18 hours a week for their employer to start having to pay national insurance for their employment.

The TUC says that like zero-hours workers, many short-hours workers don’t know how many shifts they will get each week and often have to compete with colleagues for extra hours.

Women are particularly at risk of becoming trapped on short-hour contracts, says the TUC. They account for nearly three-quarters (71.5 %) of underemployed employees on short-hours contracts.

Retail is the worst affected sector. Nearly a third (29%) of underemployed short-hour workers are employed in supermarkets, shops, warehouses and garages – nearly 250,000 people.

Education (16%), accommodation and food services (14%) and health and social care (12%) also account for large shares.

The growth in low-paid, insecure jobs since the crash has been bad for workers and the public finances, says the TUC, with taxpayers having to subsidise poverty pay through tax credits.

The TUC says that short-hour and zero-hours contracts, along with low-paid and bogus self-employment, have reduced tax revenues and are dragging down UK productivity.

Self-employment has accounted for nearly a third (31%) of the net rise in employment since 2010. Figures published last summer by the Office for National Statistics show that average earnings for self-employed workers have fallen by 22% since 2008/09.

TUC General Secretary Frances O’Grady said: “Zero-hours contracts are just the tip of the iceberg when it comes to low-paid, insecure work.

“Hundreds of thousands of other workers find themselves trapped on short-hours contracts that simply do not guarantee enough hours for them to make ends meet.

“Like zero-hours contracts, short-hour contracts give too much power to the employer. Bosses have an incentive to offer low wages and fewer hours to get out of paying national insurance.

“Without more decent jobs, people will continue to have to survive off scraps of work and UK productivity will continue to tank.”