Hundreds of thousands of disabled people are living in destitution, the first piece of research to look at extreme poverty in the UK suggests.

The study, published by the Joseph Rowntree Foundation, found that in 2015 there were 1.25 million people in the UK who were defined at some point as destitute because they could not afford the basic essentials they needed to eat, keep clean and stay warm and dry.

The ground-breaking study by researchers at Heriot-Watt University in Edinburgh did not calculate how many disabled people were living in destitution, but did conclude that one of the four most common causes of destitution was the extra costs of ill-health and disability.

And more than a quarter (29 per cent) of destitute people surveyed by the researchers said they had serious health problems.

The definition of destitution used by the researchers was that in a single month, two or more of the following had applied to a person: they had slept rough; they had had one or no meals a day for two or more days; they had been unable to heat or to light their home for five or more days; they had gone without weather-appropriate clothes; or they had gone without basic toiletries.

Two-fifths of destitute people said they had experienced delays with their benefits and 30 per cent said they had had their benefits sanctioned, while the study says that many of the most serious delays were associated with claiming or attempting to claim out-of-work disability benefits.

The study, Destitution in the UK, says that the causes of destitution relating to people’s income were “largely benefit-related”, but there were also “key triggers” around spending, including “the difficulties many encounter in meeting health-related additional expenses from extremely modest incomes”.

The report says: “Some research participants found themselves having to spend money on specific items related to their ill-health that pushed them into a destitute situation and thus they came to lack other necessities.

“Examples included people with special (and expensive) diets, and those who had to pay for taxis to hospital appointments (as their only viable transport option).”

Many of those who became destitute “faced some combination of unsustainable debts and/or unmanageable arrears repayment schedules (typically imposed by public rather than private creditors), unaffordable housing costs, other high living costs (especially energy costs), and expenditure on health and disability-related needs.

“These expenditure issues were often pivotal in pushing them from a position of severe poverty, where nonetheless they were just about managing, into a state of destitution, where they could no longer get the bare essentials.”

The study says that those who were interviewed in depth by the researchers were “quite explicit about how demeaning they found it to have to seek help with essentials like food, clothes and toiletries from charitable organisations”.

Julia Unwin, chief executive of the Joseph Rowntree Foundation, said: “There are a shocking number of people in the UK living in destitution.

“It is simply unacceptable to see such levels of severe poverty in our country in the 21st century.

“Governments of all stripes have failed to protect people at the bottom of the income scale from the effects of severe poverty, leaving many unable to feed, clothe or house themselves and their families.

“Many people affected are living on a very low income before they are no longer able to make their incomes stretch, or a financial shock like a benefit delay or family breakdown pushes them over the edge into destitution.

“We have to tackle these root causes. Government, businesses and communities need to work together to provide better emergency support, make basic essentials more affordable and create better jobs if we are to end destitution in the UK.”

The researchers surveyed people who came to voluntary sector crisis services, like foodbanks and debt advice charities, in nine areas over one week in 2015.

They used these figures, together with national statistics, to calculate the number of destitute people in the UK across the year.

But the researchers say that the true figure of people in destitution is likely to be “significantly higher” because their research did not include those people who only received help from their local council or government programmes, or those who did not seek help at all.

28 April 2016