A recurring theme of this election has been the battle for Labour’s leave-voting constituencies, the so-called “red wall” of seats running from north Wales to the Humber estuary – the seats that Boris Johnson’s “Get Brexit done” slogan is designed to win over. But despite being billed as the “Brexit” election, many of the key moments of the campaign have come back to economics: taxation, nationalisation, pensions and of course the NHS. This has clearly been a strategy by the Labour party to try to hold together its coalition of 2017 voters, who are broadly united on the economic aims of the party.

Keeping the conversation on the economy doesn’t seem to have been as successful as it might have been, with recent polls and modelling suggesting that Labour is struggling to reach the 40% share of the vote it achieved in 2017. Since the move to support a confirmatory referendum, it seems to be more successfully recapturing remain voters who had flirted with the Liberal Democrats than those who voted leave and had variously been taken by the Conservatives, the Brexit party and non-voting. Is the economic message failing to cut through to voters or are they hearing it loud and clear but are, nonetheless, unconvinced?

The problem is not that there are too few “leftwing” voters in the electorate. The British Election Study (BES) measures these political positions using a series of attitudinal statements that include “There is one law for the rich and one for the poor” and “Ordinary people get their fair share of the nation’s wealth”. Since these questions were first asked at the 1992 election, the British public have been on average slightly “leftwing”. If people voted only on their economic values, we should have had a Labour government for the last two decades. In light of its absence, it clearly isn’t just “the economy, stupid”.

The problem for Labour is two-fold. Voters do not cast their votes based on economic issues alone, and, more critically, voters on the left are divided on non-economic issues such as justice and immigration. The BES data measures responses to statements such as “People who break the law should be given stiffer sentences” and “Young people don’t have enough respect for traditional values”. People’s positions on this social dimension are statistically unrelated to their positions on the economic issues, or in the language of political science, these two sets of values cross-cut, rather than reinforce each other.

If we compare the BES results in elections 20 years apart, we see some fascinating cultural shifts. Taking only those voters whose responses place them on the economic left, we find that in 1997, it did not matter what social values they held, around 60% voted Labour. By 2017, this picture was very different. Among those economically leftwing respondents who held “socially liberal” values, almost 70% voted Labour; while among those who did not, less than 50% voted Labour, and more than a third voted Conservative. While this divergence may be part of a long-term restructuring of the vote that eventually leads to two camps reflecting a Brexit position, what is interesting is that this shift was visible in 2010, well before any Brexit realignment had begun.

This divide runs deeper than Brexit position alone, which explains why appearing more leave-leaning in leave-voting areas is insufficient for Labour to win back lost voters. Attitudes to migrants highlight the divisions that run through the potential Labour vote on the left. Asked whether they agreed that “Immigrants increase crime rates in Britain”, one in 10 of those on the economic left with socially liberal values agreed with the statement, while among those on the economic left with socially conservative values this was a little more than half. Meanwhile, more than half of the socially conservative group also agreed that “The will of the majority should always prevail, even over the rights of minorities”.

These newly salient divides among the voters on the economic left make it very difficult for Labour, whenever the conversation moves away from core economic issues. But it also makes it more difficult for the economic messages themselves to cut through to these voters. Manifesto promises can be popular in themselves, but still fail to move voters, if the party making them is not trusted to deliver. On the vital issues of trust and alienation, again we find a divide among the left’s socially liberal and socially conservative voters. Asked whether “Politicians don’t care what people like me think”, around a third of the socially liberal cohort agreed, compared with seven in 10 of the socially conservative cohort. While 44% of the socially liberal left agreed that “People like me have no say in what government does” this was 75% of the socially conservative left.

There has been considerable talk of the “politically homeless” over the last two years, and several new parties have formed in an attempt to offer them shelter. Britain’s lost voters are often assumed to be mostly centrist on economics but socially liberal and pro-remain. The performance of parties aimed at winning over these voters perhaps suggests this diagnosis was wrong.

Instead, there seems to be a potential cohort of voters who are economically left-leaning, socially conservative, voted leave and have become increasingly detached from both the Labour party and politics more generally. In 2017, there is evidence to suggest that these voters were more likely to stay at home than before. In 2019, some of these voters may move across to the Conservative party; some will vote for the Brexit party, where they have that option; others may stay at home again. But the Labour party needs to hold on to those more socially conservative voters who were willing to stick with the party in 2017; the difficulty is that their economic messages fail to cut through to voters who believe that the party is no longer listening to people like them.

• Paula Surridge is a senior lecturer at the University of Bristol’s school of sociology, politics and international studies