Shocking figures published today by the Office for National Statistics (ONS) reveal the number of workers on zero-hours contracts has rocketed by 21% over the last year, as the Unite union calls for the controversial contracts to be banned.

ONS data shows the number of workers on zero-hours contracts has soared from 747,000 to over 900,000 over the last year, as unions warn the UK labour market is increasingly creating low-paid and insecure jobs.

The number of workers on zero-hours contracts now account for 2.9% of the whole labour-force, but the ONS says the 21% rise could be due to greater awareness and recognition of the term “zero-hours contract”.

According to the ONS survey, there were 1.7 million contracts that did not guarantee a minimum number of hours, representing 6% of all employment contracts.

People on zero-hours contracts were more likely to be young, part-time, women, or in full-time education when compared with other people in employment. On average, people worked 25 hours a week – but 1 in 3 say they want more hours.

Theresa May voiced concerns over insecure jobs in her maiden speech as Prime Minister: “If you’re from an ordinary working class family, life is much harder than many people in Westminster realise.

“You have a job but you don’t always have job security”, she said.

[contextly_sidebar id=”8yYbsu4YMjznfL3xhg7iyfik8ftBLqfQ”]But Unite general secretary Len McCluskey accused the Conservatives of creating an “economy which is increasingly being built on precarious work, with more and more workers not knowing from one week to the next whether they will be able to pay the bills”.

He added: “Since the Conservatives unleashed their austerity on working people in 2010, insecure, poorly rewarded work has risen three-fold. This is the real story of the Conservatives and their stewardship of the economy – growing numbers of people trapped in the daily worry of not knowing if they will have work or can keep a decent roof over their family’s head.

“As New Zealand has shown governments do not have to sit on the sidelines when it comes to tackling exploitation. They can outlaw zero hours contracts.

“Prime minister Theresa May now needs to prove true to her word about supporting working people by setting out her plan to rid working people of the twin curses of insecurity and low paid work.

“Let’s see the UK government follow the lead of their counterparts in New Zealand and ban the use of zero hours contracts as part of a plan to halt the tide of insecure low paid work.”

TUC General Secretary Frances O’Grady said: “Zero-hours contracts have become an easy way for bosses to employ staff on the cheap. 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.

“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.

“Today’s figures are a stark reminder of why we need to create more decent jobs people can actually live on.”

A spokesperson from the Department for Business, Energy & Industrial Strategy said: “As the Prime Minister has made clear, we want to do more to build an economy that works for everyone and to help working people who are struggling to get by.

“Since May last year, the use of exclusivity clauses has been unlawful, meaning that individuals have more control over their lives and can work more hours with another employer if they wish.

“Fewer than 3% of the UK workforce classes itself as being on a zero hours contract in their main job, with almost 70% of those on this type of contract happy with the number of hours they work.”