The number of people on zero-hours contracts as their main job has increased by almost 20 per cent in the past year, from 624,000 to 744,000, official figures published this morning suggested.
The figure equates to about 2.4 per cent of all people in employment, up from two per cent this time last year.
Women made up 54 per cent of those on contracts which did not guarantee them a minimum number of hours - compared with 47 per cent in the rest of the labour market. Students - who tend to go for jobs with flexible hours - also made up a vast chunk of those on the contracts, with 20 per cent of the zero-hours workforce in full time education, compared with a mere three per cent of other workers.
The Office for National Statistics, which published the figures, suggested although the figure increased, it did not necessarily mean a large increase in the number of people on zero-hours contracts.
"Two-thirds of the increase is from people in their job for more than a year and so the overall increase does not necessarily relate to new zero hours contracts. It could have been due either to increased recognition or to people moving on to a zero-hours contract with the same employer," it said.
Yesterday investor group Pirc encouraged Sports Direct shareholders to vote against six resolutions at the retailer's annual general meeting, in part thanks tot he large number of staff employed on zero-hours contracts.
Although the government has introduced measures to reduce the number of people on zero-hours contracts, including banning exclusivity clauses, it has stopped short of banning the controversial contracts altogether.
In April work and pensions secretary Iain Duncan Smith called for the contracts to be rebranded "flexible hours contracts".
In an interview with the BBC he said workers valued the flexibility they afforded.
"Only two per cent of the total workforce have those and they are mostly people like carers, who can't give direct time, and young people like students, so for them there is a reason for those," he said.