John Curtice writes this analysis in the Times:
In 2015, David Cameron nearly strangled his Liberal Democrat coalition partners to death, capturing no less than 27 of their seats (John Curtice writes). It was a calamity from which the Liberal Democrats have struggled to recover. But now, it seems, they may pose a threat to the Conservatives once more.
The Liberal Democrat performance on Thursday was not quite unprecedented. The party’s vote was at least as high in 2019. However, that ballot took place in particularly propitious circumstances. Theresa May was struggling to get her party to back her Brexit deal, and some voters who opposed Brexit were attracted by the Liberal Democrats’ promise of a second referendum.
However, apart from that occasion, this was the party’s best local election performance since it made the fateful decision in 2010 to enter government with the Tories.
This advance has had no discernible connection with Brexit. It was just as strong in heavily pro-Leave wards as it was in the most pro-Remain. This suggests that the Liberal Democrats are recovering their mantle as the principal party of protest, a development that means it can win in pro-Leave parts of Britain once more — as illustrated by its success in winning control of Somerset.
There was a pattern to the party’s performance, however, and it is one that will especially concern Tory MPs.
First, the Liberal Democrat vote rose most in the more rural parts of the south and Midlands of England outside London — that is, in prime Tory territory. Second, Liberal Democrat support rose particularly strongly (by as much as nine points) in those wards where the party started off in second place to the Conservatives. Although anti-Tory tactical voting by former Labour voters was partly responsible for this pattern, these were also the kinds of places where the Conservative vote fell most heavily. It looks as though the Liberal Democrats feasted especially well on the apparent discontent of many a traditional Conservative voter.
There are 69 parliamentary seats in the south and the Midlands outside London where the Liberal Democrats were second to the Conservatives in 2019. Although in many of these the local Conservative MP has a large majority, they have been served notice that their seat may not be so safe at all.
In 2019, Boris Johnson could win by focusing his fire on Jeremy Corbyn’s Labour party. Next time his party may well need a strategy to deal with the Liberal Democrats too.
John Curtice is professor of politics Strathclyde University, and senior research fellow, NatCen Social Research and The UK in a Changing Europe