The number of people below the Minimum Income Standard (MIS), defined as £17,100 for a single person or £18,900 each for two working parents with two children, rose by four million between 2008/09 and 2014/15.

This means there are now 19 million people, or 30% of the population, living below the MIS, the research by the Joseph Rowntree Foundation (JRF) said.

The think tank warned that millions of ‘Just About Managing’ families – a phrase coined by Prime Minister Theresa May – are on the tipping point of falling into poverty as shop prices rise.

Forecasts show the cost of living could be 10% higher by 2020.

The Foundation also revealed 11 million people live far short of the MIS, with incomes below 75% of the standard.

It blamed the increased numbers on rising costs and stagnating wages. A typical basket of goods has risen between 27% and 30% since 2008 while average earnings have risen by half that amount.

While employment figures out today show record levels in work, the think tank said this on its own won’t help families reach the minimum income levels for a decent standard of living.

Campbell Robb, chief executive at JRF, said: “For a truly shared society, everyone should have the chance to live a decent and secure life. These stark figures show just how precarious life can be for many families. Government focus on people on modest incomes is welcome, but it cannot be at the expense of those at the poorest end of the income scale: it must remember just about managing today can become poverty tomorrow.

“This could be a very difficult time for just managing families as rising inflation begins to bite into finely-balanced budgets. The high cost of living has already helped push four million more people below an adequate income, and if the cost of essentials such as food, energy and housing rise further, we need to take action to ease the strain.”

Robb said that the government can help in next month’s Budget by allowing families to keep more of their earnings and ensuring benefits and tax credits keep up with the rising cost of living.