The pupil premium does not effectively target the lowest income pupils, a leading academic has warned.

The funding, which gives state schools extra money to help disadvantaged pupils, was introduced by the coalition government.

It is worth £1,320 for primary and £935 for secondary pupils who have been registered as eligible for free school meals during the last six years, and rises to £2,300 for those who have been in care.

However, Becky Allen, a professor at the UCL Institute of Education, set out a series of concerns about it in a talk at the ResearchED conference.

She said: “Don’t ring fence funding for pupil premium students since they aren’t the lowest income in the school, they aren’t the most educationally disadvantaged, they don’t have a homogenous set of needs, and ring fencing distorts optimal decision making for the leadership of the school, for governors, for Ofsted.

“But do give teachers the time and the environment to work out why students within their classrooms are learning different amounts.”

She cited a 2009 paper that examined whether free school meal eligibility is a good proxy for family income.

She told the conference that it shows that "a large proportion of children who are eligible for free school meals are not actually in our lowest income households, and equally there’s a large number of children who live close to the poverty line who are not eligible for free school meals."

She added: "One of the weird things about free school meals is that because it’s attached to benefits, for the household the very act of receiving the benefits that then make them pupil premium eligible jumps their household income above another load of working poor who by the virtue of working are not eligible for free school meals.”

Professor Allen said that even if the pupil premium did target perfectly the poorest pupils, poverty is not in any case a good proxy for educational and social disadvantage.

In a blog entitled 'the pupil premium is not working' that followed her talk, she writes that “children who come from households who are time-poor and haven’t themselves experienced success at school often do need far more support to succeed at school”.

She adds that pupil premium pupils do not have homogeneous needs, and that “categorising students as pupil premium or not is a bizarre way to make decisions about who gets access to scarce resources in schools”.

In her talk, she raised concerns about the “pretty onerous expenditure and reporting requirements” attached to the pupil premium, including that schools track the progress of pupil premium pupils to show they are closing the gap.

She warned that measuring attainment gaps is “meaningless”.

Professor Allen said: “This very act of ring-fencing the money and requiring an impact statement is distorting expenditure and it’s distorting the focus away from thinking about high-quality classroom instruction, or even just hiring great staff.”

Instead, she said the pupil premium should be rolled into general school funding.