Boris Johnson failing to appeal to floating voters needed to win election, according to Tory polling guru
Boris Johnson is a turn-off for millions of floating voters who backed the Conservatives at the last election, according to a polling expert.
Tory peer Lord Hayward said there was a "striking antipathy" towards the former Foreign Secretary in traditional Tory areas like the Home Counties.
The findings are a blow to Mr Johnson, who is the bookies' favourite to succeed Theresa May as Prime Minister and has called on Tory MPs to back him by arguing that he is best placed to defeat Jeremy Corbyn and Nigel Farage.
But according to Lord Hayward's analysis of recent opinion polls, a staggering 23% of people who voted Tory in 2017 - around 3 million voters - think he would be a "very bad" Prime Minister, making it highly unlikely they would support the party next time round.
The peer said whoever becomes the next Tory leader must win over those who voted Leave in 2016 if the party is to stand any chance of victory.
However, he said they must also be "transfer-friendly", meaning they appeal to floating voters more interested in competent government.
By that measurement, Mr Johnson scores badly compared to leadership rivals Michael Gove and Jeremy Hunt.
"Boris is pitching to MPs at the moment saying 'I am the one who will win'," Lord Hayward said.
"What I'm saying is that you can't stop at Brexit and win an election. You need Brexit voters, but you need the transfer-friendly voters as well."
He added: "The polls show that a Tory Prime Minister or leader can't win without Brexiteer votes, but you also can't win without this middle ground, the people who are looking for good government."
A survey by Delta Poll asking voters to compare Tory leadership candidates to cartoon characters found Mr Johnson likened to Pinocchio, Goofy and Dumbo, Lord Hayward said.
The peer said the Conservatives face "destruction" if they appeal to Brexiteers without winning the support of floating voters as well.
He added: "Boris Johnson does attract voters, there's no question about that. But he is a classic Marmite politician and there are two sides to the argument."
Elsewhere, Lord Hayward said the polls show Rory Stewart and Sajid Javid have the most appeal among voters aged 18 to 34.
At a Tory leadership hustings on Tuesday evening, Mr Johnson warned that the Conservatives will no longer exist if the Government fails to take the UK out of the EU by 31 October.
He said: "Unless we get on and do this thing, we will be punished for a very long time.
"There is a very real choice between getting Brexit done and the potential extinction of this great party - but I believe I can take on Farage and win back the voters being won over by him."
The former Foreign Secretary continues to gain support among Tory MPs, with Julian Lewis becoming the latest to say he will vote for him.
Meanwhile, Esther McVey has insisted she has enough support to avoid the cull of candidates after Tory bosses ruled that contenders must have at least eight MPs backing them.