Bright children from poor homes can fall three years behind their more wealthy peers in reading tests by the age of 15, according to a new international analysis of the impact of poverty on educational achievement.

The report has revealed the chasm in the achievements of the brightest students from rich and poor backgrounds in 32 industrialised nations, with England, Scotland, the US, New Zealand and Chile showing the biggest performance gaps.

Nations with the smallest gaps include Iceland, Finland, Germany and Denmark. The widest gap was among girls in New Zealand, where 15-year-olds from disadvantaged homes lagged three years behind their richer counterparts in reading tests.

The widest gap for boys was in Scotland, where the poorest lagged 2.9 years behind their better-off peers. English boys from poor backgrounds came 31st out of the 32 countries, with reading skills 2.6 years behind their more wealthy peers.

Experts have blamed the gap in England on the popularity of private and selective education, which can increase existing disadvantage. The relatively slim gap in countries such as Finland has been put down to a more comprehensive system, where children from poorer and richer backgrounds are more likely to mix.

The findings were published today by social mobility charity the Sutton Trust, which is calling on the UK government to introduce a “targeted programme” to test the most effective ways for state schools to stretch the most able students from middle- and lower-income backgrounds.

The report, which bases its findings on the results of the 2009 Programme for International Student Assessment reading tests, follows a survey by England’s schools inspectorate Ofsted, which found that many state schools do not offer adequate provision for highly able students.

Teachers’ leaders complained that schools had become compelled to focus on the middle ground, in order to maintain their league table positions.

Dr John Jerrim of the University of London’s Institute of Education, author of the report entitled The Reading Gap, said: “It is well known that there is a relationship between family background and educational achievement in all countries and others have compared those groups before. But we said, ‘let’s consider the relationship between family backgrounds and high achievers and different genders’.”

He said it was “not surprising” that the gap was wide in the US, as it has a long history of socio-economic background dictating school and job success. “However, in England and Scotland overall, the achievement gap taking into account all pupils is in line with the OECD (Organisation for Economic Cooperation and Development) average, so it was surprising that the highest-achieving boys in England and Scotland stood out as much as they did.”

Professor Alan Smithers, director of the Centre for Education and Employment Research at the University of Buckingham, England, said: “The explanation for England is that students from high- and middle-income homes are much more likely to go to independent and grammar schools and leading comprehensives, because their parents are able to buy their houses nearby and that gives them the chance to develop their potential.”

MIND THE GAP

Biggest gaps between high-achieving rich and poor students in reading at age 15

Girls

New Zealand - 3 years

US - 2.4 years

England - 2.3 years

Boys

Scotland - 2.9 years

England - 2.6 years

Chile - 2.6 years

Source: Dr John Jerrim, Institute of Education, University of London.