10000
100802020204040 60 8040606080(^0100)
Con 346 Lab 193 LibDem 40 Others 71
Conservativewin
Liberal
Democrat
win
←
More
Lib
Dem
MoreConservative→
←
More
Labour
Labourwin
Conservativeseatgain
LibDemseatgain
Changesfrom 2017
Changesfrom 2017
Changesfrom 2017
326 seatsformajority
2019 projection
326 seats
326 seats
Con 359 Lab 211 LibDem 13 Others 67
2019 projection
Con 339 Lab 199 LibDem 42 Others 70
2019 projection
Thisupwardsweep
showssurgingLibDem
supportinToryseats,
butnotenoughtomake
bigseatgainsgiven
theLibDems’current
TherearefewLabour- nationalvoteshare
LibDemmarginalseats.
Labourisexpectedto
losevotesharetothe
Conservatives
TheConservativescurrentlyleadin
thebulkofLabour-Torymarginals,
thankspartlytoLibDemgains
SheffieldHallam
Lib41,Lab33,Con 26
StAlbans
Kensington
TheLiberalDemocratscouldwinseatsdirectlyfromtheTories,buthurtLabourinConservative-Labourmarginals
Projectedthree-party
voteshare,%
BasedoncurrentforecaststheConservatives
areexpectedtowina 68-seatmajority
If theLibDemvotesurgesto23%,gainedequally
fromallparties,theTorymajorityis 28 seats
If thissurgedrawsheavilyfromRemainersbacking
Labourreluctantly,theToriesgeta 42-seatmajority
2017 result 2019 projection
EnglandandWales,generalelection 2019 YouGovprojection
Sources:ElectoralCommission;BritishElectionStudy;YouGov;
ChrisHanretty,PoliticalStudiesReview, 2019;TheEconomist
TheEconomistDecember 7th 2019 85
P
erhaps theonly view shared by Brit-
ain’s big parties is that backing the Lib-
eral Democrats is a dire risk. “A vote for the
Lib Dems gets you Brexit,” Labour warns. “A
vote for the Lib Dems risks putting Corbyn
in Downing Street,” claim the Tories.
Both sides cannot be right. However,
survey data of 100,000 Britons from You-
Gov, a pollster, imply that both parties are
wrong. Because the Lib Dems have pulled
votes equally from their two rivals, further
growth in their support would probably
cost both Labour and the Tories seats.
With Labour neutral on Brexit, the Lib
Dems are the main national pro-Remain
party. Voters have noticed. YouGov’s data
show that the few Leavers who backed the
Lib Dems in 2017 largely plan to defect. But
the party should pick up a fifth of the Re-
mainers who voted Conservative last time,
and 13% of Remain-supporting Labourites.
This has doubled the Lib Dems’ vote
share, from 7% in 2017 to 14% in YouGov’s
poll. But it may not yield many new seats,
because Lib Dem voters are spread out geo-
graphically. YouGov matched personal data
from respondents with the demography of
each constituency to estimate voting re-
sults in every seat. The Lib Dems come first
in just 13.
Jo Swinson’s party has fallen back in re-
cent polls. However, late surges are com-
mon in British elections, particularly when
tactical voting is widespread. How might
the race change if the Lib Dems approach
the 23% vote share they won in 2010?
To find an answer, we scaled up their
popularity in every constituency to reach a
scenario in which their national vote share
was 23%. First, we grouped Britons based
on their Brexit vote and whom they sup-
ported at the last general election—for ex-
ample, Leavers who voted Lib Dem in 2017.
According to YouGov, just 30% of these
people plan to stick with the Lib Dems. To
get to a national share of 23%, the party
would need its support in this category to
double. Next, we estimated how many vot-
ers in each group (such as Labour Leavers)
live in each constituency, to determine the
seat-by-seat impact of a Lib Dem surge.
In terms of winning seats in England for
themselves, the Lib Dems pose a serious
threat only to the Tories. There are 13 seats
in which those two parties are the front-
runners and are separated by a single-digit
margin. Between the Lib Dems and Labour,
the only close fight is in Sheffield Hallam.
However, the Lib Dems could still hurt
Labour, by taking votes from the left-wing
party and letting the Tories sneak through.
This is especially likely in Tory-Labour
marginals in the north and Midlands.
Which of these two effects is larger de-
pends on tactical voting. We explored two
endings for our hypothetical scenario: one
in which Lib Dems surge uniformly, and
one in which they disproportionately rally
in seats where their former supporters
have reluctantly flipped to Labour, hoping
to prevent a hard Conservative Brexit.
If the swing is uniform, the Tories will
lose out most, with perhaps 25 seats going
from blue to yellow. If tactical Labour vot-
ers flock back to the Lib Dems, it will be Je-
remy Corbyn who suffers more. But in both
cases, late gains for Britain’s third party
would leave the main two worse off. 7
If the Lib Dems surge, they could hurt
the Tories as much as Labour
Yellow submarine
Graphic detailBritain’s election