Nearly five millions British workers are being paid less that what is required for a basic standard of living, according to a new study.
It found 4.82 million people are being paid below the Living Wage, a pay packet which enables the basic standard of living.
The rate currently stands at £8.30 an hour in London and £7.20 in the rest of the UK.
It is a voluntary rate, unlike the National Minimum Wage - the amount that employers must pay by law - which is set at £6.19 an hour for those aged 21 and over.
Accountants KPMG, which carried out the study, said lower paid workers are feeling the impact hardest, with more than four in 10 (41%) saying that their finances are worse now than they were just one month ago.
Marianne Fallon, head of corporate affairs at KPMG, which has itself signed up to pay the Living Wage, said: "Times are difficult for many people, but of course those on the lowest pay are suffering the most."
She added: "Tackling in-work poverty is vital if we are to enable more people to improve their life prospects and increase social mobility in this country."
The report revealed workers in the hospitality industry are the worst affected, with 90% of bar staff paid lower than the living wage.
Furthermore, three quarters (75%) of kitchen and catering assistants, as well as launderers and dry cleaners, were paid less than the living wage.
Rhys Moore, director of the Living Wage Foundation, said: "Paying a Living Wage makes a huge difference to the quality of life of thousands of cleaners, caterers and security staff across the country.
"It is really encouraging to see nearly 100 organisations now signed up and accredited, but that still leaves many more organisations that aren't."
The report suggested that Northern Ireland had the highest proportion of people earning below the Living Wage, at 24% of workers, followed by Wales at 23%.
The lowest levels were in London and the South East of England, both at 16%.