Nearly a third of people in the UK have fallen into poverty at least once in four years, according to new figures.
Women are more at risk of experiencing longer term poverty than men, the analysis by the Office for National Statistics (ONS) also suggests.
The gap between men and women remaining in poverty over several years has been "relatively stable" at 1.5% but the UK was behind countries including Lithuania, Spain and Poland.
The overall UK poverty rate in 2014 was, at 16.8% of the population, 12th highest compared with 27 other European Union countries.
But Britain had the third-lowest rate (6.5%) of those remaining in persistent poverty over three years or more, equivalent to around 3.9 million people.
The poverty rate was calculated based on the number of people whose income after tax is less than 60% of the national average - equivalent to £9,956 for a single person without children and £20,907 for a family of two adults and two children.
Richard Tonkin, head of household and income expenditure statistics at the ONS, said: "Over a four-year period it's actually surprising how high the proportion of the population is whose incomes slip below that.
"In the UK, compared with other countries, people have a relatively high risk of slipping into relative low-income poverty.
"But high exit rates mean people are much more likely to escape poverty than in other countries."
Poverty tended to be "transient" for many people in the UK and was strongly linked to the labour market, with those finding employment having a greater chance of escaping, Mr Tonkin said.
This meant people who were considered "poor" were "constantly changing" year on year, he added.
The report found that between 2011 and 2014, almost a third (32.5%) of the UK population experienced poverty at least once.
Of those in persistent poverty for three or more years between 2011 and 2014, 9.8% were women and 7.7% of men.
It said: "Single-adult households with dependent children are far more likely to contain women and ... are also more likely to be in persistent poverty."
Persistent poverty rates for single people with children had fallen by nearly half in six years, from around 30% in 2008 to around 15% in 2014.
Households with single people were more likely to remain in poverty for longer than households with two adults, the report added.
And people who left school without any formal qualifications were twice as likely to experience poverty at least once between 2011 and 2014 than those with a degree or higher.
A Downing Street spokesman said: "Relative poverty in 2013/14 - which is the most recent year for which data is available - was at its lowest level since the 1980s, income inequality is lower than it was in 2010, and living standards rose to their highest ever level in 2015.
"The Government is determined to tackle poverty and its causes, particularly through work. One million fewer people on the main out-of-work benefits shows that work is the best route out of poverty and we are making progress there."