The number of UK workers on zero-hours contracts has risen by 21% compared to the previous year according to figures from the Office of National Statistics and the Labour Force Survey (LFS), a survey of households.

The latest estimate from the LFS shows that 903,000 people reported that they were on a zero-hours contract in the period April to June 2016, representing 2.9% of people in employment. This is 21% higher (156,000 higher) than the reported figure from the same period in 2015 (747,000 or 2.4% of people in employment). In recent years, increases in the number of people reporting to the LFS that they were on a zero-hours contract were likely to have been affected by greater awareness and recognition of the term zero hours contract. This latest annual change may also have been affected in this way but it is not possible to estimate the extent.

When looking at the length of time in current job, 66% of the increase in zero-hours contracts is from people in their job for more than a year, that is, they were already with their current employer in April to June 2015. This could reflect either increased recognition or people moving on to a zero-hours contract with the same employer. The number of people on a zero-hours contract who had been in their current job less than a year also increased. This could have been due either to a rise in the prevalence of zero-hours contracts or to increased awareness of the terms of the contract when people start work.

People on zero-hours contracts are more likely to be young, part-time, women, or in full-time education when compared with other people in employment. On average, someone on a zero-hours contract usually works 25 hours a week. Around 1 in 3 people (31%) on a zero-hours contract want more hours, with most wanting them in their current job, as opposed to a different job which offers more hours. In comparison, 10% of other people in employment wanted more hours.

Nearly half the increase seen in zero-hours contract workers over the past year was among workers aged between 25 and 64, raising concerns about job stability for people likely to have dependents. Over a third of zero-hours workers are aged 16-24, and one in five said they were in full-time education.

As well as the number of contracts, the business survey also estimated that 10% of businesses make some use of contracts that do not contain a minimum number of hours (NGHCs)

 “Zero-hours contracts have become an easy way for bosses to employ staff on the cheap,” TUC General Secretary Frances O’Grady said. “There is no getting away from the fact that zero-hours workers earn less money and have fewer rights than people with permanent jobs.

“It is very easy for politicians and employers to talk about the ‘flexibility’ these contracts offer. But they are not the ones living at the sharp end of the labour market, O’Grady said. “If you don’t know how much work you will have from one day to the next, paying the bills and arranging things like childcare can be a nightmare.

TUC analysis shows that the typical UK employee earns 50% more an hour than the typical worker on a zero-hours contract. The median hourly rate for a zero-hours worker is £7.25, while for all employees it is £11.05.

“For some, zero hours contracts are symbolic of Britain’s job-creating labour market flexibility, while for others they represent the deep insecurity that belies the recent jobs recovery,” Conor D’Arcy, Policy Analyst at the Resolution Foundation, said.

“The fact that the use of zero hours contracts has grown –and the Prime Minister has chosen to highlight the issue of job insecurity in her maiden speech – mean that they need far closer, and more measured, scrutiny,” D’Arcy said.

“Banning Zero Hours Contracts outright is a misguided approach that risks penalising those workers, such as some students and those with caring responsibilities, who genuinely prefer the flexibility afforded by them. But many workers who are on a Zero Hours Contract want more stability, reliable hours and greater protection. Helping them get this should be a priority of this government,” D’Arcy said.