The Conservatives have used a “sleight of hand” to justify their manifesto pledge to create new grammar schools, a leading academic has claimed.

The Tory manifesto says official research shows that “slightly more children from ordinary, working class families attend selective schools as a percentage of the school intake compared to non-selective schools”.

However, Alice Sullivan, head of the department of quantitative social science at the UCL Institute of Education, described this claim as “staggering” and “clearly false”.

She said it was only reached by excluding poorer families from the definition of “ordinary, working class families”.

“Very far from producing evidence-based policy, they are flying in the face of all the evidence we have,” she said. “Even more shockingly, they are using quite clear sleight of hand to misrepresent the evidence and claim that grammar schools are taking their share of ordinary working class kids.”

Becky Francis, director of the UCL Institute of Education was speaking at the same event: a media conference held by Education Media Centre, in Central London. She criticised Conservative plans for more universities and private schools to sponsor academies or set up free schools.

She said: “There is really no evidence that the input of universities and private schools as sponsors is going to help raise quality here. There has been an incredibly mixed picture.”

And Becky Allen, director of Education Datalab described the Conservative pledge to bar councils from creating new places at schools rated ‘inadequate’ or ‘requires improvement’ as “infeasible”.

She said this was because some of the need was driven by “very, very short term” demographic pressures, and setting up new free schools takes a long time.

The Conservative Party has been contacted for comment.

Dr Allen described Labour’s plans, meanwhile, as essentially a “manifesto for teachers”.

She said this was “no bad thing”, as the absolute constraint on getting a better education system now was constraints in the teacher labour market.

However, she added: “I don’t think [Labour] has a coherent vision of what sort of education they’d like for children. When I read this manifesto, it’s hard for me to understand what kind of material changes to the experience of children, particularly in the classroom, they want to see happen.”

She said the Liberal Democrat manifesto pledges on reducing political control over the curriculum, slimming down on the core curriculum, and Sats reform, would have “a material impact on the experience of children in the classroom”.

However, she said that while they had “lovely policies” on professional development of existing teachers, they had “nothing” to deal with “the critical problem” of teacher recruitment.