The percentage of households that fall below society's minimum standard of living has increased sharply over the last 30 years, despite the size of the economy doubling, experts say.
Researchers who carried out the largest study of poverty and deprivation conducted in the UK found the figure had increased from 14% to 33%.
The study said almost 18 million people cannot afford adequate housing conditions, while 12 million are too poor to engage in common social activities.
One in three people cannot afford to heat their homes properly in winter, with four million children and adults not properly fed by today's standards.
Experts, who are calling on the Government to take action, say their research shows full-time work is not always sufficient to escape poverty.
Findings from the project, Poverty and Social Exclusion in the United Kingdom (PSE), based on two surveys, will be discussed at a conference in London this week.
Professor David Gordon is from the Townsend Centre for International Poverty Research at the University of Bristol, which led the project involving 14,559 people in the UK.
"The available high-quality scientific evidence shows that poverty and deprivation have increased since 2010, the poor are suffering from deeper poverty and the gap between the rich and poor is widening."
The research was conducted by the University of Bristol, Heriot-Watt University, the Open University, Queen's University Belfast, University of Glasgow, University of Oxford, University of Birmingham, University of York, the National Centre for Social Research and Northern Ireland Statistics
and Research Agency.
It found around 5.5 million adults go without essential clothing, while 2.5 million children live in damp homes. Around 1.5 million children live in households that cannot afford to heat their home.
One in four adults has an income below what they consider is needed to avoid poverty, while one in every six adults in paid work is poor. More than one in five had been forced to borrow in the last year
to pay for day-to-day needs.
The study, funded by the Economic and Social Research Council, showed more than one in five adults and children were poor at the end of 2012.
They had a low income and were "multiply deprived" - suffering from three or more deprivations such as a lack of food, heating and clothing due to not having enough money.
In 1999, the percentage of households in arrears on bills was 14% but this rose to 21% in 2012, with the most arrears being utility bills, council tax and mortgage or rent.
Professor Jonathan Bradshaw, from the University of York, said the research dispelled the myth that poverty, especially child poverty, is a consequence of a lack of paid work.
The study found the majority of children who suffer from multiple deprivations live with one or two siblings, with both parents, have at least one employed parent, are white and live in England.
About 28% of adults have skimped on their own food in the past year so others in their home could eat. Despite this, more than half a million children live in families who cannot afford to feed them properly.
Prof Bradshaw said: "The research has shown that in many households parents sacrifice their own welfare - going without adequate food, clothing or a social life - in order to try to protect their children from poverty and deprivation."
In 93% of households where children suffered from food deprivation, at least one adult "sometimes" or "often" went without food to ensure others had enough to eat.
Women were more likely to cut back than men, with 44% curbing four or more items such as food, clothes and social visits in the last 12 months, compared with 34% of men.
Research found wages are low and working conditions bad in many parts of the UK. One in six adults in paid work suffers from a low income and cannot afford basic necessities.
Full-time work is not sufficient to escape from poverty for a "large number of people", with almost half the employed poor working 40 hours a week or more.
Nick Bailey, from the University of Glasgow, said: "The UK Government continues to ignore the working poor; they do not have adequate policies to address this growing problem."
The study found more people today see a range of public services - including libraries, sports centres, museums, galleries and dentists - are "essential" than in 1999.
However, since 1999 the use of many services has declined, primarily due to reduced availability, cost or inadequacy.
Professor Glen Bramley, from Herriot-Watt University, said: "It is worrying that in the 21st century more than 40% of households who want to use meals on wheels, evening classes, museums, youth clubs, Citizens Advice or special transport cannot do so due to unavailability, unaffordability or
However, use and adequacy of a few universal services, such as buses, trains, corner shops and most children's services, has risen since 1999.
The research had a special section on people's experiences of violent events during the Troubles in Northern Ireland, which examined events including death and injury of close friends and relatives.
Overall, more than a quarter of adults in Northern Ireland lacked three or more necessities, but the deprivation rate was 36% in those who lost a close friend.
The rate was 38% for those who had a close friend injured, 43% for those who witnessed an assault and 45% for those who had a close relative who spent time in prison.
It rose to 56% for those who had their house searched by the police or Army and 58% for those who moved house due to attack, intimidation, threats or harassment.
Professor Mike Tomlinson, from Queen's University Belfast, said: "Research in many parts of the world has shown that violent conflicts can result in long-term problems of poverty and deprivation.
"This is what has happened in Northern Ireland. The evidence is clear. Dealing with the past needs to include tackling the deprivation of those whose lives are most blighted by the years of conflict."
The findings will be discussed tomorrow and Friday at the 3rd Peter Townsend Memorial Conference in London.
The researchers found 33% of households were multiply deprived - meaning they go without three or more of the basic necessities of life.
These basic necessities were defined as items or activities that more than 50% of the UK population believes everyone should be able to afford and should not have to do without.
They include being able to adequately feed and clothe themselves and their children, and heat and insure their homes. All of these households are not necessarily below the poverty line.
Researchers used the three or more deprivations formula to establish the minimum standard of living, as it is directly comparable with methods used to study poverty and deprivation in 1983.
A Department for Work and Pensions spokesman said: "There is strong evidence that incomes have improved over the last 30 years, despite the misleading picture painted by this report.
"The independent statistics are clear, there are 1.4 million fewer people in poverty since 1998, and under this Government we have successfully protected the poorest from falling behind with a reduction of 300,000 children living in relative income poverty and 100,000 fewer children in workless poor families.
"As part of our long-term economic plan, the Government is committed to tackling the root causes of child poverty."