Britain is facing a literacy crisis which will leave nearly 1.5 million 11-year-olds unable to read properly by 2025, unless action is taken, and is depriving adults with limited reading skills of appropriate help.

A coalition of charities, teachers and publishers will today launch a campaign to reverse an educational failure which means that thousands of children, many of them poor, are leaving primary school each year unable to read well and likely to struggle for the rest of their lives.

A report by “Read on. Get on.” said England is now one of the developed world’s most unequal countries in reading with the gap between the strongest and weakest equivalent to seven years of schooling. Only Romania has a worse record among EU members.

The problem is acute in low-income groups, in particular white British boys, where 45 per cent reach 11 unable to read well. A total of 40 per cent of poorer children are not proficient readers – almost double the rate of their better-off peers. The proportion of children reading well by 11 has dropped by 1 per cent in five years since 2008. Even with an average annual improvement rate of 0.5 per cent, an estimated 120,000 pupils a year will fail to reach a proficient level of literacy – a total of 1,440,000 children between 2013 and 2025.

Through measures such as supporting parents to read with young children for 10 minutes a day and seeking volunteers to help disadvantaged children, the body aims to have all children reading well by 2025. It said its goal was to ensure that all 11-year-olds can read, understand and discuss stories such as Harry Potter.

Research by Newcastle University for the report found the emergence of a “book gap” in Britain, with almost a quarter of 11-year-olds having fewer than 10 books in their home. By contrast, if all children were reading well by that age, GDP in 2025 would be £32bn higher, according to the study.

Dame Julia Cleverdon, chairwoman of the campaign group, whose members include Save the Children and publisher HarperCollins, said: “It is tragic and unfair that children from the poorest families and the most deprived communities are least likely to read well at the age of 11 in the UK, one of the wealthiest countries in the world. This vital long-term campaign aims to make a life-changing difference for children in poverty and society.”

In a separate study published today, MPs condemned the Government as “short sighted” for cutting the budget for adult literacy and numeracy training and said should it should reverse it decision to remove £2.5m of funding from a scheme by the trade union movement’s education arm.

The Business, Innovation and Skills (BIS) Select Committee said levels of adult literacy and numeracy in England were “alarmingly low” and the Government was missing an opportunity to raise economic productivity.

The committee said there was a particular problem with the least literate and numerate adults being able to get help and support because they did not know it was available. Advertising of free adult literacy courses ended in 2010.

Adrian Bailey, chairman of the committee, said: “A national campaign will get the message out to those who are most in need of support.”

The Government defended its record, saying the gap had narrowed. Backing the campaign, the Education Secretary, Nicky Morgan, said: “We know there is more to do, which is why our new curriculum has a greater focus on reading.”

CASE STUDY: the volunteer dad

Damien, 39, from Sheffield, and his wife, Nicola, have six children, ranging in age from 18 months to 15 years. Damien volunteers with Families and Schools Together (Fast), an early-intervention programme that brings parents, children, teachers and the wider community together to make sure the children get the support they need to do their best at school.

You’ve got to instil a joy of reading at a young age. Every night, I call the children together for reading time. I’ll read to them while they have their milk.

I never did much with my mum and dad; I was basically just left to my own devices to do what I wanted. I taught myself things because I had to, so I’m trying to pass on as much as I can to my own children.

I took on the role of a Parenting Partners facilitator in the Fast programme at my children’s school. I undertook two days of training and then ran a hub supporting other parents and children through the programme.

With Fast, the parent spends 15 minutes with just one child every week. My son Lucas is five. We did notice a change in him – he became more forward and he’s got more confidence than before.