She is a chemical engineer and he a painter turned security guard -- the Koleshevs are the hidden face of the "working poor" in Bulgaria, the EU's most impoverished country.

"Our salaries amount to about 950 leva (485 euros, $495) per month," Katia Kolesheva, 49, tells AFP in the family's one-bedroom flat in the town of Buhovo outside Sofia that they share with their 24-year-old son.

"When we pay the monthly instalment on a loan and our bills, we are left with 200-220 leva for food. That's all for the three of us."

According to an EU-wide survey, 48 percent of Bulgaria's 7.2 million people live in "material deprivation", defined as being unable to afford things like adequate heating or meat every second day.

Seven to eight percent of these are so-called "working poor" like the Koleshevs, employed but struggling to make ends meet, with every unplanned expenditure potentially spelling disaster.

The family say they had to skip an instalment on an 8,000-euro loan -- taken out to buy their music student son a violin -- in order to buy firewood last winter.

"Going on vacation is out of the question. In 26 years we have been on holiday twice," Katia's husband Mircho, 60, says. Going to the movies, the theatre or a cafe is "unthinkable".

The grey-haired man, a painter with a degree from the National Academy of Arts in Sofia, works as a night guard at the local community centre, where he also teaches a children's drawing course.

He and Katia often borrow coins from their son, who busks to make ends meet.

"The grocers here frown when they see me coming with the jar. They are fed up with me already. I go to the big supermarkets in Sofia where they can't refuse the coins," Mircho says.

- Grinding poverty -

National statistics show that one in five Bulgarians is "relatively poor" -- living on 60 percent of national median income -- and one in every 10 lives in absolute poverty.

Another EU survey in March found that Bulgaria was also the bloc's unhappiest country.

The long-term unemployed, widowed pensioners and multiple children families, especially from the 10-percent Roma minority, are the hardest hit. But they are not the only ones.

Some 170,000 people or eight percent of all employees who receive the minimum monthly salary of 184 euros also come close to the poverty line after paying insurance and tax.

Experts say that the situation is the legacy of successive governments after the end of communism in 1990 failing to implement reforms to make the economy more competitive and attract investment.

Bulgaria was hit by a banking crisis and hyper-inflation in the mid-1990s but with IMF help achieved 10 straight years of economic growth between 1998 and 2008, joining the EU in 2007.

But then the 2008-9 global financial crisis hit, costing the country an estimated half a million jobs, and sending improvements in living standards into reverse.

"Other eastern (European) countries managed to catch up with the EU but they started the reforms earlier," Institute for Market Economy expert Petar Ganev told AFP.

"The other reasons are structural -- traditionally low economic activity, the lowest in Europe with very few people working, and the severe ageing of the population," he added.

- No new shoes -

The Koleshevs' problems began at the end of 2008 when the biggest steel mill in the Balkans, where Katia had worked as a chemical engineer for 18 years, went bankrupt and laid off over 5,600 people.

She is owed more than 6,000 euros of unpaid salary and compensation but she has no hope of ever getting the money.

She now earns only about half of her previous salary and commutes for two hours every day to and from her job in a Sofia laboratory and babysits on Saturdays to try and make ends meet.

"During the 25 years of transition from communism, people lost hope that there is a chance for things to get better and that we can exit this situation of constant privation and penury," she said.

"It's not just the privation... One does not only need bread, or yoghurt or food. I last bought a pair of boots back in 2007!"