The analysis above cannot tell us whether these divides within the electorate are enduring parts of the landscape or new. However, as the same question was asked previously, it is possible to compare the significance of these factors among the two parties’ supporters in Audit 4 and Audit 15.

Most important when deciding which political party to vote for:

* Indicates that the change is statistically significant.

The results set out in the table above indicate that while the divide over the importance of competence is not new, the divisions over policy and leadership are. Conservative supporters have become significantly less policy-focused by 2017, compared to the 2006 sample. Conversely, they have become a great deal more focussed on leadership.

The data also shows that priorities have changed most among Conservative supporters: none of the shifts observed among Labour supporters is statistically significant.

Because the Audit has not tracked this question each year, it is not possible to determine whether the change in attitudes among party supporters has occurred gradually since 2006 or is a more recent phenomenon. However, both the 2015 and 2017 election campaigns run by the Conservative Party were heavily personalised. Personalised campaigns are not unique to the Conservatives by any means, but they have employed them both more intensively and more recently.

The recent Conservative campaign – and David Cameron’s re-election campaign of 2015 – were fought, in large part, on the basis that the party had a superior leader to that of the Labour party, with policy often being downplayed. Bale and Webb claim that the 2017 Conservative campaign was ‘exceptionally presidential’ – best demonstrated by its campaign leaflets which neglected local issues and focused instead on presenting its candidates ‘standing with Theresa May’.

It seems likely that Conservative supporters have become more leader-focussed and less policy-focussed since the 2015 general election

Changes in the voting coalition might also play a role. Research by Bartle suggests that older voters are more likely to be leadership voters. As the Conservative Party has become steadily more dependent on older voters since 2010, its overall coalition may have become more concerned with leadership.

Other sources of data would support the suggestion that the crucial shifts have occurred in recent years, particularly since 2015. The ‘Political Triangle’ surveys conducted by IpsosMORI have tracked people’s priorities for their vote intermittently since the 1980s, comparing the effects of leaders, policies and parties.

IpsosMORI ask people to allocate ten ‘points’ according to the importance of each factor to their vote. In pre-election surveys in 2005, 2010 and 2015, they found that there were only small differences in the mean number of points that Conservative and Labour supporters gave to policy and leaders. In 2017, however, leaders were significantly more important to Conservatives than Labour supporters, and policy was more important to Labour supporters. While some aspects still remain in doubt – we do not know when and why competence became more important to Conservatives – it seems likely that Conservative supporters have become more leader-focussed and less policy-focussed since the 2015 general election.

Conservative support appears to be heavily dependent on perceptions of competence. As such, if political events conspire to provide a negative shock to that sense of competence, at least some Conservative voters could withdraw their support from the party. The principle risk, in this regard, centres on Brexit: as Green and Jennings have pointed out, should the Conservatives preside over a major crisis then the situation could significantly hurt the party’s reputation for competence.

In contrast, declining confidence in Jeremy Corbyn among 2017 Labour supporters, as found in recent opinion polls, may matter less than some commentators think because Labour supporters do not appear to set as much store by leadership when deciding who to vote for. While many may still withdraw their support from Labour, the Audit data would suggest this is far from certain.

McKay, L. (2018) How important are competence and leadership in people's party choice? (Hansard Society: London)