More than 5 million workers across Britain are in low-paid and insecure work, leaving families struggling to make ends meet, according to a campaign calling for more firms to offer guaranteed hours to their staff.

According to research published by the Living Wage Foundation, workers in Wales, the north-east and West Midlands experience the highest rates of low-paid insecure work in the country.

More than 2 million parents and 1 million young adults lack adequate working hours and pay to make ends meet, with millions of workers facing cancelled shifts, while a disproportionate amount of people from black and minority ethnic backgrounds are also affected.

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The study comes as the campaign group behind the real living wage – a voluntary pay level designed to reflect living costs, set at £9 across the country and £10.55 in London – extends its campaign from focusing on pay levels to also encourage firms to provide guaranteed shift patterns and minimum working hours.

Designed as a kitemark for employers in addition to living wage accreditation, firms signing up to the Living Hours pledge must commit to provide workers at least four weeks’ notice of shifts and a contract with a guaranteed minimum of 16 hours a week.

Katherine Chapman, director of the foundation, said: “A lack of secure, stable hours is leaving millions of families struggling to keep their heads above water. This isn’t good for workers or businesses.”

Major living wage employers including the retail chain Richer Sounds, the energy supplier SSE and fund manager Standard Life Aberdeen have committed to sign up to the pledge, while other firms are expected to do so. There are currently more than 5,000 living wage employers.

Julian Richer, the founder of Richer Sounds, who said last month he would hand over control of the hi-fi and TV chain to staff, giving employees large cash bonuses, said he thought it made business sense to pay the living wage and offer secure contracts.

“We just need more businesses to realise this. Offering Living Hours is a great way to provide workers with security, but it’s also going to help businesses in the long run,” he said.

Instead of relying on voluntary measures, some countries have legislated to protect workers from exploitation from insecure work and zero-hours contracts, while there are calls in Britain for ministers to take similar steps. Official figures show zero-hours contract usage has begun falling, although it remains high at 884,000. Labour has said it would ban zero-hours contracts.

John McDonnell, the shadow chancellor, said: “While the Tory leadership hopefuls slug it out over tax cuts for the wealthy, this is the reality of low wages for so many in the country.”

In France, part-time contracts must provide a minimum of 24 hours per week, while Norway restricts the number of workers that can be employed on a fixed-term basis.

There have been calls in Britain to force companies to pay higher minimum wages to workers on zero-hours contracts. The Taylor review of employment practices, set up by Theresa May to examine issues in the gig economy, recommended such steps were considered. However, the government’s independent Low Pay Commission has since dismissed the approach.

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According to the Living Wage Foundation, more than a fifth of the workforce in Wales are in low-paid and insecure jobs, about 300,000 people. Scotland had the lowest rate of job insecurity and low wages in the country at 13%, followed by the south-east and London.

Compiled using government figures by the New Economics Foundation thinktank, the study defined insecure work as being when people are on casual, seasonal, fixed-term and agency contracts, excluding those who do not want a permanent job. It also includes zero-hours contracts and self-employed people.