Folk musician Eliza Carthy recently wrote of how appalled she was to find herself listed as one of BNP leader Nick Griffin's favourite musicians. And who can blame her?

But this episode goes deeper than one folk singer's embarrassment. Griffin's championing of English folk music is one element of a wider cultural strategy being pursued by the BNP. This involves forging a connection between the deeply felt sense of socio-economic marginalisation prevalent in some communities and the more overt espousal of pro-English, as opposed to pro-British, nationalism.

This shift in cultural politics on the far right is a prescient and overlooked one. According to research shortly to be published by the Institute for Public Policy Research, an attachment to Englishness has become a more significant feature within the social culture of England than many of our politicians have realised. This trend has also become powerfully intertwined with divisions associated with class.

Various factors have helped strengthen English identity over the last decade. Devolution has forced the English to reflect on their own sense of nationhood and position in the union. The recognition that England is governed in an extraordinarily top-down fashion has generated a sense of concern about its (un)democratic position that spans the camps of right and left. Just as important has been a general trend towards the revival of some of the ancient ties of belonging in the face of the changes and insecurities associated with globalisation.

Our research points to the Janus-faced character of this new sense of Englishness. On the one hand, a distinct English national iconography has quite rapidly become part of the wallpaper of our cultural life. Think of how commonplace the cross of St George, once a symbol tainted by association with the far right, has become. In this and many other guises – such as a notable revival of English musical traditions, literature and art – we found that English self-identification carries no single political or social agenda. Nor does the strengthening of Anglo identities necessarily mean that people cease to care about Britain. The evidence suggests that for most people the opposite is true: valuing your Englishness has for many people added to the stock of multiple identities that we enjoy holding.

So what's the problem? Well, a second trend has also come into play. A much shriller and often chauvinistic idea of English identity has emerged as an important vehicle for the expression of a growing sense of resentment among some sections of the English populace. It is this new breed of populist nationalism that is putting a gleam in Nick Griffin's eye.

This is the brand of English nationalism that many liberal commentators and politicians, including the current prime minister, rightly see as a toxic antithesis to the civic and inclusive patriotism which they want to see grounded upon a broader sense of Britishness.

Understandable as this recoil is, our research leads us to question this widely held progressive position. First, we found that the belief that government and polite society disapprove of Englishness is a key ingredient in the soil in which populist nationalism has flourished. A concerted progressive engagement with English identity and culture would help starve this unpleasant plant of much of its oxygen.

Second, it is about time that we dumped the caricature of the white working class, which infantilises public debate. It is simply not true that white working-class people are more prone to populist nationalism than their middle-class counterparts. In fact, what struck us most about the conversations we had with people from different backgrounds during our research were the different ambitions and fears associated with a commitment to being English. We became aware of a complex and shifting set of arguments about what it means to be English today.

And, third, we need to question the widely held assumption that Englishness is "for whites only". It is true that polls tend to suggest that the majority of ethnic minorities in England connect with the idea of being British rather than English. And there are good reasons why liberals are sometimes suspicious of the assertion of English pride. But closer inspection of the evidence suggests a more complex picture. Attitudes to English identity vary between and within ethnic minority communities, while there is anecdotal support for the idea that people from third-generation backgrounds are more ready to identify with aspects of English culture and identity.

We should recall too that on some important social issues, including attitudes towards racial mixing and community cohesion, England remains one of the most tolerant developed countries in the world. Progressive and multicultural English patriotism represents an important means of seizing back the ground that the far right is trying to occupy. A good start would be for all mainstream political parties to combat the insinuation that Englishness is "forbidden" in our cultural life.