Thread by @ElectionMapsUK

Combined weighted national polling from the month before #LE2016 & #LE2017:

CON: 42.0%
LAB: 29.5%
UKIP: 10.3%
LDM: 8.5%
GRN: 3.3%

So by my calculations, LAB need to be within 12.5% of CON in national polling to have a net swing of seats to them in #LE2021.

February 2021 Polling:

CON: 41.6% (-0.4)
LAB: 37.6% (+8.1)
LDM: 6.6% (-1.9)
GRN: 6.3% (+3.0)
RFM: 1.7% (NEW)

Changes w/ 2016-17 combined estimate.

Easy to see how even on a disappointing night for LAB, there should be a fair old swing to them in terms of seats.

Just to breakdown the combined national polling figure for transparency:

LE2016 (2,769 seats)
CON: 35.3%
LAB: 31.9%
UKIP: 15.8%
LDM: 6.0%
GRN: 3.9%

LE2017 (4,851 seats)
CON: 45.9%
LAB: 28.2%
LDM: 10.0%
UKIP: 7.2%
GRN: 2.9%

So seats last up in 2017 could see HUGE swings...