Theresa May slipped up when she claimed that only a “very small" group of workers were on zero-hours contracts despite numbers soaring since 2010.
Labour leader Jeremy Corbyn used the first Prime Minister’s Questions after the summer recess to challenge Ms May on how "inflation was running ahead of people's pay" as McDonald’s staff took strike action for the first time over working conditions and zero-hours contracts.
Opposition MPs jeered when the Prime Minister said these contracts could be "beneficial" to the "very small" group of workers, yet official figures suggest more than 900,000 people were employed under these terms in December last year.
Pressed on the issue, she said: "Obviously the matter taking place in McDonald's is for McDonald's to deal with. Let's focus on what you have raised about things like zero-hours contracts.
"In fact, the number of people of zero-hours contracts is very small. There are people who genuinely say - as a proportion of the workforce - who genuinely say it is a benefit to them to be on those contracts."
Ms May said Labour had failed to tackle the issue during its years in government whereas the Tories had "put the workers first" and banned exclusivity clauses.
However Mr Corbyn hit back, saying there were thousands of people on zero-hours contracts and urged her to condemn the disparity in pay between ordinary workers and top staff at the fast food chain.
Figures from the Office for National Statistics show that 905,000 people were employed on zero-hours contracts as their main job between October and December last year, compared to 168,000 in 2010.
Mr Corbyn also said the Prime Minister had "gone back on her word" to crack down on executive pay packages by ensuring they were subject to strict annual votes by shareholders.
The Labour leader drew laughs form the Tory benches when he pressed Ms May on Sports Direct, adding: "She's not the only one going back on her word..."
He said: "At last year's Sports Direct annual meeting, Mike Ashley personally pledged to ban the use of zero hours contracts in his company.
"A year on, they're still exploiting insecure workers with zero hours contracts. Will the Prime Minister join me in now demanding that Mr Ashley honours his words and ends zero hours contracts in all his companies?"
Mrs May repeated that the Government has taken action over zero hours contracts.
