Around five million British workers are not paid enough to cover their basic needs, according to a report due out tomorrow.
Shops and restaurants are among the worst offenders, say campaigners, who are expected to call for an increase in the living wage. This is £8.80 an hour in London and £7.65 an hour elsewhere; the statutory minimum for those aged over 21 is £6.50.
However, the living wage is not statutory and many businesses – including all of Britain's top retailers – choose not to pay it.
Tomorrow's figures, from the Living Wage Foundation, are expected to reveal that sales and retail assistants are the most likely to earn below the living wage. About 750,000 such workers earn close to the minimum. Their wages are supplemented with in-work tax credits – meaning that taxes are subsidising the profits of private companies, according to campaigners.
"Many people are working two and three jobs just to make ends meet," said Rhys Moore, director of the Living Wage Foundation.