In the study, published by The Royal Statistical Society's journal, Significance, the Oxford University researchers tracked the views of 22,300 people across the UK, surveying them first in February 2014 and then in the autumn of the same year, on the leadership qualities of David Cameron, Ed Miliband, Nick Clegg and Nigel Farage.
They were asked to rate each on a 10-point scale, according to who they 'strongly liked' or 'strongly disliked', and also gave information about other issues likely to affect their voting behaviour. The researchers found that among those surveyed over seven or eight months, Farage attracted around 17% of new support to UKIP, with a personal rating 'far higher' among the vote-switchers than for any other party leader.
Even those who had left UKIP were only slightly less positive towards Farage. However, the study highlights that less than 75% of those surveyed who said they backed UKIP initially were still supporting them later, compared with 85% for the Conservatives and 84% for Labour. The study shows how UKIP depends far more than other parties on its leader's own popularity for winning votes.
The analysis also shows that although Cameron's overall approval among his supporters remained steady over the period of the study, he was responsible for between 10%-14% of all Conservative defections of those surveyed, but still attracted around 17% of the new recruits over the same period.
Miliband was found to be responsible for between 8%-10% of defections from Labour over the period last year but, unlike Cameron and Farage, did not attract new recruits to Labour. Among Liberal Democrat supporters, Clegg's support declined slightly and he had more or less no effect in recruiting supporters either over the same period, says the study.
As well as tracking each person's feelings towards each of the party leaders over the study period, the researchers also calculated for other factors likely to affect voting behaviour such as a person's attachment to a particular party, how the party was viewed for dealing with important issues facing the country, and attitudes towards immigration and income redistribution.
Study co-author Professor Geoffrey Evans, Official Fellow in Politics at the University of Oxford, said: 'Our study shows the pressure on Nigel Farage to keep UKIP afloat is immense. While the leaders of other big parties can count on their parties' own solid support base, UKIP's popularity as a party appears to rely to a greater degree on how the public perceives Farage.
The Labour and Conservative parties are established parties and often have long-standing support, but the new kid on the block, UKIP, has no reservoir of identity or traditional support base. Our findings suggest that improvements in media performance by any of the leaders can still help a party – even if not by such a large degree – when the time comes for the public to cast their votes.'
Co-author Dr Jonathan Mellon said: 'While opinion polls can tell us about public attitudes towards political leaders at a particular moment in time, this study tracks the feelings of more than 22,000 people over many months.
'The media coverage of the General Election of 2015 has concentrated heavily on the personal qualities of the different party leaders, arguably like never before. While it has long been assumed that a leader's image influences votes, this academic study provides the first evidence of just how much of a factor the party leaders could be in the forthcoming election.'
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