A controversial poster campaign unveiled by UKIP this week has put immigration front and centre in the campaign for the local and European elections next month. But while political parties grapple with the impact of immigration on longer-established communities and job markets, research elsewhere suggests the changing voting patterns of immigrant communities themselves pose different challenges.

Authored by ex Labour politician and former Equalities and Human Rights Commission boss Trevor Phillips, in partnership with University College London geography professor Richard Webber, the paper due on Friday in Demos Quarterly will suggest that upwardly mobile ethnic minorities moving to predominantly white middle class areas may ditch their Labour allegiance. Reports in the Telegraph and Times see this as good news for the Conservatives in Tory marginals. The report’s authors suggest that the effect – even when the relatively small numbers of upwardly mobile ethnic minorities are taken into account – could make an impact in constituencies such as Hendon and Wolverhampton South West. But it’s worth waiting for the full report before Tory strategists get too excited.

The emerging numbers show that just 20% of ethnic minority voters change allegiance from Labour to the Tories when moving to the suburbs. Others may switch to alternative parties or stay loyal. If I were a Labour candidate targeting a Tory marginal, would I rather face the challenge or retaining a previous Labour voter new to the constituency or a longer term resident who voted Tory last time? I’d rather tackle the former and welcome some new blood. Even if my new neighbour votes Lib Dem, they might be replacing a Tory voter moving out to the countryside.

But while local implications are debatable, though interesting to the media, the big-picture messages seem clearer.

Firstly, voting intentions correlate with socioeconomic status. This comes as no surprise. The correlation of voting intention with ethnicity may at least in part be a consequence of ethnic-minority communities tending to be less well off than longer-established communities and not a result of party policies on ethnicity or immigration.

Secondly, voters – whether in ethnic minorities or otherwise – can no longer be thought of as coherent blocks. In ethnic-minority areas, political organisers have historically vied for the favour of influential community leaders who were expected to deliver the community vote. The Respect Party demonstrates that this sort of politics isn’t dead. However, as political party loyalty continues to decline across the board and political choice is widening with the growth of smaller parties and niche pressure groups attuned to individual views, voter engagement needs to be ever more personal. No voter can be taken for granted.

Faced with this more complicated picture, the Prime Minister’s sweeping generalisation about the UK being a Christian country seem out of place. But given the way in which people of other faiths have supported the assertion, there is evidently a further level of complexity at work. Religion and ethnicity are not the same, and people of faith – any faith – may have more in common with each other than with non-believers. By recognising the importance of one faith, perhaps Cameron is nodding to the importance of them all.