Anti-poverty campaigners have been targeting Tesco shops in an attempt to pressure the company into paying staff the Living Wage.
Doctored food labels have been popping up in shops, calling for the company to give their employees a pay rise.
The calls come as new research from the Living Wage Commission, chaired by the Archbishop of York John Sentamu, found that the majority of people living in poverty in the UK are from working households.
The Living Wage is the minimum amount necessary to enable workers to provide for their own basic needs. The rate is currently at £8.80 in London and £7.65 in the rest of the UK. The National Minimum Wage is currently £6.31.
Working poverty and growing income inequality has been identified as an important electoral issue, and Labour have said they will "significantly" raise the minimum rate.
Rhys Moore, Director of the Living Wage Foundation, said one of the issues is that minimum wage rates of pay have become an acceptable benchmark of earnings for some employers, instead of the "absolute legal floor" it was intended to be.
The minimum wage was there to provide an absolute legal floor, and if employers break that they are breaking the law. It was designed to help spot the worst type of exploitation.
It was never meant to be a going rate for work, or a recommended wage.
A former Tesco worker has started a petition calling for the company to adopt the Living Wage, and the thousands of names will be presented at the company's AGM this Friday.
Former Tesco till worker and manager Amy Bradley said the company needs to improve pay as the current rates are not enough to survive and thrive on.
I worked at Tesco for the majority of my adult life and saw first-hand the many problems created by poverty pay.
Too many of my colleagues struggled to get by even with a full time role. Many juggled multiple jobs to make ends meet.
Again and again, good people left the company because they couldn't earn enough to provide for themselves and their families.
Research from the TUC said a breakdown of official figures showed that around 20% of workers across the UK were taking less than the living wage.
In some areas this number rises to almost 50%, with London and areas in the south of England being the areas where the most underpaid workers live.
Tesco said they already pay the Living Wage, if the benefits and rewards package offered to staff was included in the calculation. A spokesperson said:
We pay one of the highest hourly rates in the industry, on average between five and eight per cent more than our major competitors.
The Living Wage only recognises basic pay, but our reward package is much broader than that. When our colleague discount, Shares in Success scheme and employer pension contributions are taken into account, all our staff receive above the living wage, both in London and in the rest of the UK.
Rhys Moore from the Living Wage Foundation called on Tesco to take the lead on the issue of poverty wages, and commit to raising the game across the retail sector.
The strong feeling is that the Tesco workers want this, Tesco customers want it, and this would be a great opportunity for Tesco. People really care about this, and would be willing to spend their money in shop that pays the Living Wage.