The number of British households falling below minimum living standards has more than doubled in the past 30 years, despite the size of the economy increasing twofold, a study on poverty and deprivation in the UK claims .

According to the study, 33% of households endure below-par living standards – defined as going without three or more "basic necessities of life", such as being able to adequately feed and clothe themselves and their children, and to heat and insure their homes. In the early 1980s, the comparable figure was 14%.

The research, billed as the most detailed study ever of poverty in the UK, claims that almost 18 million Britons live in inadequate housing conditions and that 12 million are too poor to take part in all the basic social activities – such as entertaining friends or attending all the family occasions they would wish to. It suggests that one in three people cannot afford to heat their homes properly, while 4 million adults and children are not able to eat healthily.

Having someone in the household in work does not prevent British families from facing tough living conditions, according to the research, undertaken by the Poverty and Social Exclusion project (PSE). It found that many households that were struggling had at least one adult in work.

Experts who produced the research, which will be discussed at a conference in London on Thursday, are calling on the government to take action to counter the problems they have pinpointed.

Their findings will be seized on by opponents of the coalition, who argue that good news about the economy does not mean living standards are improving for most people. This will be a key Labour message in the run-up to next year's election.

Other figures being published include the claims that 5.5 million adults go without essential clothing; that 2.5 million children live in damp homes; that 1.5 million children live in households that cannot afford to heat them; that one in four adults have incomes below what they themselves consider is needed to avoid poverty, and that more than one in five adults have to borrow to pay for day-to-day needs.

Prof David Gordon, from the Townsend Centre for International Poverty Research at the University of Bristol, said: "The coalition government aimed to eradicate poverty by tackling the causes of poverty. Their strategy has clearly failed. The available high-quality scientific evidence shows that poverty and deprivation have increased. The poor are suffering from deeper poverty and the gap between the rich and poor is widening."

Led by the University of Bristol and funded by the Economic and Social Research Council, the PSE project's research will be presented to the conference and published in full this week. Gordon said he had been shocked by some of the findings. "In the early 1980s we assumed life was going to get better. For many it has, for many it hasn't."

According to the research, which also involved universities in Glasgow, York, Oxford and Northern Ireland, 21% of households are behind with household bills, against 14% in the late 1990s. More than one in four adults (28%) have skimped on their own food so that others in the household might eat.

The PSE project argues that its findings dispel the idea that poverty in general and child poverty in particular is a consequence of a lack of paid work. It found that the majority of children who suffer from multiple deprivations live in small families with one or two siblings, with both parents, have at least one parent who is employed and are white.

However, the situation is not all bad, according to the research. Usage and adequacy of some universal services such as buses, trains, corner shops and most children's services has risen in recent years.

The findings will be discussed at the Peter Townsend memorial conference beginning in London on Thursday.