The label "white working class" is not helping the people it refers to, two think tanks have claimed.
Researchers say the phrase has been "all talk and no action" and that the "left behind" include white and ethnic minority working class people.
The joint report from the Runnymede Trust and CLASS argues that helping all deprived communities is the key to improving things for the white working class.
Dr Omar Khan, director of the Runnymede Trust, said: "The white working class have more in common with poor ethnic minority communities than they do with the white middle and upper classes.
"Poor white and BME (black and minority ethnic) people are bound by shared experiences of social deprivation, but there is also more social interaction between them than between the richest and poorest thirds of white people."
He added: "The label white working class isn't helping the white working class because it is all talk and no action.
"Rather than offer a desperate and empty form of ethnonationalism, the best way to raise up this section of society is for central and local government to adopt policies to benefit all working class communities."
The think tanks are calling on Home Secretary Amber Rudd to resurrect a measure obliging public authorities to take into account disadvantage and inequality when making decisions about policies.
Known as the "socio-economic duty," the requirement was included in Labour's Equality Act but was abandoned within months of the 2010 election.
Dr Faiza Shaheen, director of CLASS, said the Brexit vote is "now being used to justify an idea of 'white self-interest"'.
She added: "If we are to have a truly 'United' Kingdom we must return to speaking about the real issues that hurt the whole working class - low wages, the housing crisis and devastating cuts to our public services.
"At a critical juncture in UK history, we cannot afford to let the divisive white working class narrative continue unchallenged."