by John Curtice and Stephen Fisher, 1^st May 2024.

Seats won and lost in the local council elections in England this week may be a poor guide as to how well the parties performed. Since the elections are held under single or multi-member plurality, without any increase in support a party may make big gains in seats off the back of another party losing votes. A third party whose vote is geographically spread may make a substantial advance in votes yet reap little reward in terms of seats. Meanwhile, seats won and lost only provide an indication of whether a party has lost or gained ground as compared with when the seats up for grabs were last contested.

These caveats are important again this year. Around 70% of the council seats up for grabs this year were last fought over in May 2021. Boris Johnson was Prime Minister and the Conservatives were successfully claiming the credit for an early Covid vaccine rollout. The party enjoyed a six-point lead in the polls, gained over 200 seats in the local elections and recorded their best performance in terms of votes since 2017.

The Conservatives therefore face the challenge this week of defending a strong baseline while running 20 points behind in the polls (an even weaker position than this time last year). They look set to make significant losses. Other parties, such as the Liberal Democrats, may gain seats purely as a result of the decline in support for the Conservatives, without necessarily attracting more voters themselves.

That said, one key uncertainty is that Reform UK are only fielding candidates in one in six of the wards where local elections will take place. According to the polls, the Conservatives are now losing more of their 2019 voters to Reform than any other party. Perhaps some of these voters will switch to the Conservatives where Reform are not on the ballot paper, thereby helping to stem Conservative losses. 

Yet we cannot assess party performance by simply adding up the votes cast (even if we had the resource to collect them all on election night). In England (unlike Scotland and Wales) it is never the case that the whole country votes in local elections at the same time. The places that vote one year are politically different from those that vote in another.

This year’s local council elections, for example, are taking place disproportionately in urban England outside London, whereas last year most rural parts of the country did go to the polls. At the same time, in three-quarters of councils only one in three (or in a few cases one in two) of the council seats are being contested this year, whereas elsewhere all the seats are. 

Given all these difficulties, for over 40 years, a key measure of party performance at local elections has been the BBC’s ‘projected national share’ of the vote (PNS). This is an estimate of the share of the vote that the principal parties would have won if, across Britain as a whole, voters had behaved in the same way as those who did vote in the wards that were contested by all three principal parties in this year’s English local elections. It provides a single, seemingly straightforward measure of party performance that can tell us not only how well or badly a party has done as compared with four years ago, but also as compared with previous local elections – even though the places in which local elections are held varies considerably from one year to the next.

Yet almost inevitably answering such a ‘what if’ question is not as straightforward as it might seem. Given the large number of wards being contested, the calculation of the PNS has to be made on the basis of a sub-sample of the local contests. None of the parties fight all of the wards being contested, and some may well fight fewer wards than others. At the same time, local election results in England tell us nothing about the performance of the nationalist parties in Scotland and in Wales. Any estimate of the PNS is affected by the decisions that are made about how best to address these issues.

Consequently, it is not surprising that there have sometimes been differences between the PNS we have calculated for the BBC at previous local elections and that calculated by the local election experts, Colin Rallings and Michael Thrasher (Associates of Nuffield College Oxford), whose National Equivalent Vote (NEV) appears each year in The Sunday Times, and last year on Sky News too. Those differences have typically been limited with neither the PNS or NEV consistently better or worse for any party. That said, since 2015 there has been a tendency for the PNS to be higher than the NEV series for the Liberal Democrats and Others, and correspondingly lower for the Conservatives and Labour. Some of the possible reasons were discussed in a previous blog post. 

One of the key features of British electoral behaviour since the EU referendum has been a strong link between party support and whether people backed Leave or Remain. Leave voters – and Leave voting areas – are more Conservative, while Remain supporters – and areas – are relatively Labour. This pattern has also been reflected in local elections. Consequently, since the Brexit referendum it matters a lot whether the councils up for election are disproportionately in Leave voting areas or Remain supporting ones. 

This year around 2600 seats in 107 council areas are being contested in provincial England (that is England outside London). At 54%, the average 2016 Leave vote in places with local elections this year, is somewhat above the 52% who voted Leave across Britain as a whole. After all, Leave only won 43% in Scotland and Wales combined, both of which have no local council elections this year.

London was also a part of Britain that was reluctant to leave the European Union. The capital does have elections for the Mayor and Greater London Assembly (GLA) this week, but no elections for London borough councilors, that is, the direct counterparts of the councilors being elected elsewhere in England. GLA election results have never been part of the PNS calculation. This year the votes for the Assembly members will not be counted until Saturday, while the BBC will hopefully be broadcasting the PNS on Friday afternoon.

Local elections between 2017 and 2021 saw Leave voting areas swing disproportionately to the Conservatives. However, over the last two years Leave voting areas have swung disproportionately back to Labour in local elections (see here and here). That means the past two years have seen the geographical Brexit divide unwind somewhat. In 2022 the Brexit divide in Conservative and Labour support was still strong, just a little weaker than it was in the 2021 local elections. It weakened further at the 2023 local elections. This year we may find that the Brexit divide is on a par with last year, or perhaps narrower still. 

As we described in 2018 here, in 2019 here, in 2021 here, and 2022 here the regression and projection methodology we have developed in recent years (which rests on comparing the parties’ performances this year with multiple previous years) takes into account both (i) any different patterns of change since different baseline years in Leave and Remain areas, and (ii) the balance of Leave and Remain support in local authorities in places with local elections as compared with those without. 

Although most attention is focused on the Conservatives’ performance, the PNS will also provide valuable guidance on the strength or otherwise of the performance of the opposition parties.

Although Labour’s lead over the Conservatives in the general-election vote-intention polls is higher than last year, Labour’s own standing is not. Unlike the tally of seats won and lost, the PNS will tell us whether that message from the polls is confirmed or not.

Meanwhile, in the hope of building on their successes of last year, the Liberal Democrats and Greens are fielding candidates in 78% and 74% of wards respectively. Those figures are up from the corresponding figures of 69% and 66% for last year. The increased competition from the Liberal Democrats and Greens might make it more difficult for Labour to register an advance.  However, both the Liberal Democrats and the Greens’ standing in the polls is no higher than last year either, so they both will be keen to demonstrate that they, too, are doing more than profiting from Conservative misfortune.

John Curtice is Professor of Politics at the University of Strathclyde.

Stephen Fisher is Professor of Political Sociology at the University of Oxford.