Primary schools in England have been accused of “social segregation” after a report showed more than 1,500 schools were turning away disadvantaged pupils in favour of children from higher-income families.

A report from the Sutton Trust found some of the most popular primary schools – particularly faith schools – had complicated oversubscription criteria that actively discouraged parents of poorer children and allowed the schools to be selective about which pupils were granted a place.

The findings have raised concerns about a lack of equity in access to primary schools resulting in pupils from lower-income backgrounds potentially missing out on places at top-performing state schools.

Dr Rebecca Allen, who co-authored the report, said: “There are some parts of the country where many schools are accepting some children ahead of others – what we found is that those children had a social profile that was more affluent than the neighbourhoods that they were recruiting from.

“The main way that a child would get a place at a school ahead of someone living closer to that school is through religious selection – and it happens that children who attend church for example tend to be from wealthier families.”

The report found a direct correlation that showed the most popular primary schools used more complex criteria for selecting new students.

British primary schools typically use around five different criteria, but of the most socially selective primary schools, at least one detailed as many as 18 oversubscription criteria.

These included “giving a high priority to looked after children sharing the faith of the school”, “prioritising attendance at named churches over a long period of time” and “prioritising children of staff”.

In several instances, schools were found to be in breach of the Admissions Code.

Christine Blower, General Secretary of the National Union of Teachers (NUT), said: “It is important is that every child from whatever background has access to a good local school which draws from a balanced intake across the local community and reflects all levels of ability and background.

“There need to be clear criteria that give all parents a chance to secure their child a place in their local school.  Complicated admissions policies with conditions that potentially exclude local children of whatever social background are detrimental to education and communities.  Policy-makers need to understand what is happening beneath the radar of their school reforms – education is becoming an instrument of social segregation, not an answer to it.”

The findings come as thousands of parents across the country wait to be told which primary school their child will be offered a place at in September.

According to the researchers, places at Church of England schools are increasingly competitive in correspondence to often soaring Ofsted reports and higher achievement rates.

Dr Allen said: “There is a reason these schools are popular – they are often successful and have historically been so.

“If we want to keep criteria for large religious schools to select [new admissions], I think we need to dampen down the effects of that – either by allowing for a select number of places available on religious ground or a number of places left for the local community.”

Of all the schools surveyed, there were more than 1,000 primary schools where the proportion of pupils taking free school meals was more than 10 per cent lower than that found among children in the neighbourhoods from which they recruit.

Chris Keates, General Secretary of the NASUWT, criticised Government policy for allowing “selection by stealth” among higher achieving schools.

“There is a national admissions code which applies to all schools which is supposed to make sure that admissions are as fair as possible,” she said.

“However, the increasing fragmentation of the system as a result of Government policy has removed robust oversight and scrutiny of this code.

“The consequence is that there is now ‘selection’ rife in the system, with those from the poorest backgrounds being disadvantaged.

“This has been compounded by the fact that key provisions and safeguards in the admissions code have been removed or diluted by the Government, with much of it now being ‘non-statutory’, meaning that schools are not required to follow it.

“Consequently we now have selection by stealth, as practices are introduced which are designed to deter children from socio-economically deprived backgrounds with increasing numbers of  parents  unable to secure a place in their local school.

“As a result of Government policy, children and young people from disadvantaged backgrounds are being denied the entitlements they should expect from a public education system.”

It comes as the Institute for Fiscal Studies warned spending per primary school pupil would fall 7% in real terms between 2016 and 2020.

The economic think tank said this would be the largest real-terms fall over any period since at least the late 1970s, but added that due to substantial growth in the 2000s, real school spending per pupil in 2019–20 would still be more than 50% higher than in 2001.

Lucy Powell MP, Labour’s Shadow Secretary of State for Education, said: “Parents will be very surprised to learn that schools’ budgets face real cuts after the Prime Minister personally promised to protect their budgets at the last election.

“Schools will be forced to reduce the number of teachers and teaching assistants and stop funding extra-curricular activities. These cuts will have a huge impact on standards and outcomes.

“At the same time, this Government’s costly reorganisation of our schools system, forcing every primary and secondary school to become an academy by 2022, will remove even more money, time and effort away from where the focus in schools should be – on raising standards. This unnecessary and unfounded distraction to academise all schools is the wrong priority and harms standards in the classroom.”