[2][3] YouGov defines the blue wall as seats which are "currently held by the Conservatives; voted to Remain in 2016; and have a higher-than-average concentration of degree holders in the population (25%+).
[9] Starting in December 2021, with the 2021 North Shropshire by-election, the usage of this term has evolved to mean any seat which the Conservative Party has traditionally held.
[11] In February 2022, think tank Onward posited that the north of England—as part of the red wall—would be "the principal battleground in the next general election" with there being "no evidence of a southern 'blue wall' ready to fall".
However, Onward did admit that certain seats "in London and the south-east are drifting away from the Tories and could fall in two or three elections' time", with data analyst James Blagden observing that "[t]he heart of the Tory party has been shifting northwards for the last 30 years" yet any potential of their "traditional southern heartlands slowly drifting away" existed in the long-term, with their "greatest short-term concern" being "backsliding in the red wall, losing their iconic 2019 gains, and putting their majority at serious risk.
"Rishi Sunak is perfectly capable of appealing to blue wall seats, but he's the leader of a party that people have seen over quite a long period of time heading in a particular direction.
[14] Campaigning in the 2024 local elections, Ed Davey said he was confident of toppling the "Tory Blue Wall in Surrey".