Graduates gather outside Senate House after their graduation ceremony at Cambridge University Reuters

A government adviser has said that working class children should act like their peers from wealthier families if they want to achieve more in life.

Peter Brant, head of mobility at the Social Mobility and Child Poverty Commission, said children from less well-off backgrounds needed to be more comfortable with how middle class people eat, dress and socialise if they wanted to get into the best universities and jobs.

Writing on the commission's official blog, Brant said poorer children were missing out on applying for top universities because they were worried about not "fitting in" and needed to be more comfortable with "alien middle class" situations like going to restaurants and theatres.

He said: "It seems likely that worries about not fitting in will be one reason why highly able children from less well-off backgrounds are less likely to apply to the most selective universities.

"It probably contributes to a lack of confidence amongst those who are upwardly mobile as they struggle to adapt to their new social environment with detrimental impact on their ability to reach their potential.

"And the lack of effective networks and advice to help navigate this new alien 'middle class world' probably make it more difficult to translate high attainment into success in the professional jobs market."

Brant's post was in response to an article he read about a student feeling "significantly outside of my class" whilst at Cambridgeshire University.

The author stated: "Middle class is a scary place, full of unwritten rules that are alien to someone coming from a background where survival is paramount.

"Coming from lower-income backgrounds, we start off feeling inferior because life and our experiences have told us that we are. We then risk continuing to feel inferior because we are stuck in circles surrounded by people who constantly have access to knowledge and cultural experiences we haven't."

John Major, the former prime minster, recently said it was "truly shocking" how the privately educated and "affluent middle class" still ran the country.

Education secretary Michael Gove has also spoken about how he intended to reform the school system so "the opportunities that wealthy children have are more equally spread".

Brant, who studied at Cambridge, added: "One helpful thing would be more awareness of this as a potential issue – it can often be unappreciated by policy makers who mostly come from middle-class professional backgrounds.

"This often means that debate can all too easily assume that if educational inequalities can be reduced and aspirations of young people from working-class backgrounds raised then that alone will be enough to tackle the problem."