The majority of people younger than 55 do not support the expansion of grammar schools, a new poll reveals.

The Survation poll for the Mail on Sunday shows that just 33 per cent of 18 to 34-year olds and 32.7 per cent of 35 to 54-year-olds support the policy. But among the over 55s, a slight majority (50.9 per cent) think it is a good idea.

Men (45 per cent) were also more likely to say they supported the expansion of grammar schools than women (34.3 per cent).

The survey was conducted via an online poll of 1,017 adults in the UK.

The Conservative Party confirmed plans to expand grammar schools in its manifesto this week.

“Contrary, to what some people allege, 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,” the party’s manifesto states.

But a day after the manifesto was published, new research on the impact of selection found that only a third of children from “just about managing” families in selective areas are likely to obtain a place at a grammar school.

The research from the UCL Institute of Education, University of London, the University of Bristol and University of Warwick added that selective education harms the university prospects of bright pupils who did not manage to get into a grammar school.