New analysis this week showing that 14 million people live in poverty highlights just how unequal a society the UK has become. Poverty is particularly prevalent among disabled people, single parents, unemployed people or those working irregular or zero-hours jobs.

It follows recent research by the OECD showing that social mobility has stagnated, with a child from a poor family in the UK taking five generations on average to earn the average wage, compared to two generations in Denmark, and three in Finland, Norway and Sweden.

It’s hardly surprising, according to Kate Pickett and Richard Wilkinson. The married academics’ 2009 book, The Spirit Level, on the effects of inequality on societies across the world, sold over 150,000 copies in English alone, and was lauded across the political spectrum.

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Nine years on, things have not improved. The Inner Level, their long-awaited follow up published earlier this year, looks at the more personal, individual effects of inequality: how the social effects of the gap between rich and poor impact on people. “We’re talking about how inequality affects our intimate lives, our inner lives; our mental wellbeing, our relationships with friends and family,” Pickett says.

The Inner Level examines a society that has dealt with 10 years of austerity, and seen almost every family impacted by stagnant wages, increased job insecurity, swingeing cuts and changes to the benefits system and public services nationally and locally, as well as a surge in problems with mental health across society. “It takes a whole argument and evidence about the effects of inequality to a deeper and more intimate level. In The Spirit Level we were dealing with things about society ‘out there’ – the size of the prison population, homicide rates, obesity rates and so on. But this takes it into the sphere of our social fears and anxieties,” Wilkinson says. “Worries about self worth: all the things that make social contact sometimes seem rather awkward and stressful. Your fears about self presentation and so on are all exacerbated by inequality.”

Facebook Twitter Pinterest ‘Measuring the levels of the stress hormone cortisol in infants found that poverty, and the amount of time spent in poverty, can hamper the mental development of children.’ Photograph: Photofusion/REX/Shutterstock

The problems scrutinised in the book – self doubt, social anxiety, stress, and fear of how we are seen by others – have an impact on day-to-day emotions for individuals, but also a wider impact on relationships, our ability to build functioning communities, and the health and wellbeing of entire populations. These issues are massively exacerbated by inequality, and a belief in meritocracy means that any failure is deemed a personal failure, the book argues. “The reality is that inequality causes real suffering, regardless of how we choose to label such distress. Greater inequality heightens social threat and status anxiety, evoking feelings of shame which feed into our instincts for withdrawal, submission and subordination: when the social pyramid gets higher and steeper and status insecurity increases, there are widespread psychological costs.”

The stress of poverty also influences the cognitive development of babies and children. Measuring the levels of the stress hormone cortisol in infants found that poverty, and the amount of time spent in poverty, can hamper the mental development of children. Pickett and Wilkinson find that “family income is a more powerful determinant of cognitive development than being brought up by single parents, or maternal depression”, and that if children are enrolled in support services like Sure Start and their equivalents in other countries, some of the effects of poverty are offset, and children’s educational and psychological performance improves.

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The social demarcations of class, from what we eat and how we talk, to what culture we consume, are also rigorously upheld in more unequal societies, making discrimination much easier and preventing social mobility. In more unequal societies, the book finds, fewer people marry someone of a different class background, the number of visits to art galleries and museums is lower, the prison population is higher and the age of criminal responsibility for children is lower.

Wilkinson and Pickett cite extensive statistical evidence that unequal societies are responsible for less fulfilling personal lives, and in turn harm public health, scupper educational progress, increase crime and lower life expectancy. “We debunk some of the myths that people use to explain why [society] is willing to tolerate greater levels of inequality, namely that inequality is a natural result of our human nature, that we are competitive, individualistic and out for ourselves – that’s the way we are, it’s just human nature and nothing can be done about it,” Pickett says. “That is not the case. We also provide evidence to counter the argument that actually we’re living in a meritocracy, and that inequality is simply a case of the capable and talented moving up, and those who are less capable, less clever, moving down.”

Many of the problems in our increasingly polarised society are down to social inequity and are not natural, they argue. “Inequality itself creates these differences,” Pickett says. “Increased social anxieties and worries about how we are seen damage social life and lead actually to more violence. The worst affected withdraw from life entirely, and even among the rest of the population who don’t feel it so acutely, we all feel it a bit,” Wilkinson warns. “Thatwhile Wilkinson warns that inequality “diminishes social life. What we value most is laughing, joking, relaxing and spending time with friends and family. That is essential to health and happiness – and yet it’s there that inequality strikes.”

If the pair were given power tomorrow, they already have a few policy priorities. “I’d ban private education to put a brake on intergenerational unfairness, in line with Finland. But I’d also institute an exceptionally large inheritance tax,” Pickett says.

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Wilkinson concurs, but adds: “I think we have to extend democracy into the economy, and hugely inflated salaries have to be stopped. We should have employee representation on company boards, and incentives to grow cooperatives and employee-owned companies. That whole sector has to grow.”

Curriculum vitae

Age: Kate is 53, Richard is 75.

Lives: They live together near York.

Family: Richard and Kate have been married for six years; they each have a son and daughter from previous relationships.

Education: Kate: Ecclesbourne school, Derbyshire; University of Cambridge (biological anthropology); Cornell University, USA (nutritional sciences); University of California, Berkeley, USA (epidemiology). Richard: the Quaker school, Leighton Park; LSE (economic history); University of Pennsylvania, USA (regional science); University of Nottingham (epidemiology).

Career: Kate: University of Chicago, 1999-2003; University of York, 2003-present, where she is now university research champion for justice and equality. Richard: Avon Area Health Authority, 1979-81; University of Sussex, 1981-2001; University of Nottingham, 2001-2008. They co-founded The Equality Trust (with Bill Kerry) in 2009.

Interests: Both love walking and the countryside. Kate also loves cooking and ballet (both dancing and watching); Richard pursues his interests in fossils, archaeology and anthropology.