Conservative MP and leadership contender Boris Johnson gestures as he addresses the final Conservative Party leadership election hustings in London | Tolga Akmen/AFP via Getty Images EXCLUSIVE POLL Boris Johnson toxic with Scots and Lib Dem voters: poll Tory leadership front-runner’s negative ratings among key groups will make it hard to construct a majority.

LONDON — A Conservative Party led by Boris Johnson would struggle to build a majority at the next U.K. general election because of the prospective leader's toxicity with key groups of voters, exclusive polling for POLITICO suggests.

According to the data, Johnson as leader would likely face a perfect storm of losing seats in Scotland and failing to win over centrist voters in Tory-Lib Dem swing seats.

A poor performance on both fronts would close off two avenues that kept the Tories in government at the last two general elections.

Theresa May clung on to power at the 2017 snap election by winning 12 seats in Scotland (up from just one at the 2015 election). Had she not done so, she would not have been able to cobble together a majority in the wake of the shock result with the help of the Democratic Unionist Party.

But according to a POLITICO-Hanbury poll that drilled into voter attitudes in four clusters of swing constituencies in England and Scotland, Johnson — the frontrunner in the Tory leadership race — is electorally toxic north of the border.

When compared with his rival, Foreign Secretary Jeremy Hunt, Johnson is viewed as best suited to be prime minister in three out of the four electoral battleground regions polled: the East Midlands, the North West and London.

But in Scotland, the figures are reversed. Just 19 percent of respondents there said Johnson would make the best premier, while 32 percent opted for Hunt.

In the Leave-voting East Midlands, 34 percent of respondents said Johnson would make the best prime minister compared with 22 percent for Hunt, while in London 36 percent chose Johnson and 30 percent picked Hunt. And in the Leave-voting North West, Johnson scored 29 percent and Hunt 24 percent.

Scots, meanwhile, say they think Johnson would be more likely to win an election but that Hunt would do a better job of managing Brexit by 26 percent to 24 percent.

When voters were asked whether each of the candidates would make them more or less likely to vote for the Conservative Party, Johnson fared particularly badly in Scotland. His net score (the percentage of voters saying he would make them more likely to vote Tory minus those saying he would make them less likely) was -29 percent. That is more negative than in any of the other regions polled and lower than Hunt's -15 percent net score in Scotland.

Meanwhile, the data suggests a Johnson premiership would struggle to attract centrist voters. Cameron won an outright majority for the Tories in 2015 by seizing swathes of the Lib Dem vote share and snatching seats off his coalition partners in the process.

The POLITICO-Hanbury poll suggests that strategy would not work for Johnson. In all four regions, Johnson's net score among Lib Dem voters is strongly negative, indicating he would repel the centrist, pro-EU party's supporters.

In the East Midlands, the net score is -60 percent; in London it is -45 percent; in Scotland it is -73 percent and in North West it is -58 percent. In all cases, his score is more negative among Lib Dem voters than it is among those who identify as Labour or Scottish National Party supporters.

However, the data do suggest that Johnson is best placed to win back Tory voters who have drifted to the Brexit Party. He is by far the preferred candidate among supporters of Nigel Farage's party in all the battleground regions except Scotland.

The poll included 3,066 respondents and was conducted between June 21 and July 15.

Because of the focused nature of the poll it does not provide a national figure for voting intentions. It is part of a series POLITICO and Hanbury is publishing this year, tracking public opinion in blocks of neighboring constituencies throughout the country. By creating clusters from constituencies with similar political and demographic features, the aim is to understand what is really happening in some of the key constituencies that will decide the next election.

POLITICO and Hanbury identified four clusters for the series: the central Scottish seats of Airdrie and Shotts, Motherwell and Wishaw, Dunfermline and West Fife, Kirkcaldy and Cowdenbeath, Falkirk, Linlithgow and East Falkirk; the central London seats of Battersea, Putney, Kensington, Cities of London and Westminster, Chelsea and Fulham; in the North West, there's Cumbria’s Morecambe and Lunesdale, Barrow and Furness, Workington, Copeland and Carlisle; and finally the East Midlands marginals of Mansfield, Bolsover, Broxtowe, Amber Valley, Ashfield, North East Derbyshire and Chesterfield.

You can find more details on the methodology of POLITICO-Hanbury polls here, as well as other polls in the series.

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