Voters in England and Wales will cast ballots for mayors, council members and police commissioners on Thursday. And while the elections will, of course, focus on local issues like garbage collection and public safety, this vote is expected to have broader significance.

Why does this election matter?

Local elections, by their nature, are about who leads communities and ensures the delivery of certain public services. But many analysts believe the results of these elections will also serve as an important bellwether of general public opinion across England and of whether Prime Minister Rishi Sunak’s beleaguered Conservative Party has a chance of retaining power in a general election expected this fall.

The Conservatives face a fierce challenge from the opposition Labour Party, led by Keir Starmer.

The Conservatives won a third successive general election in 2019, but the accumulated discontent of 14 years in power — a period that included several changes of prime minister and political scandals — is weighing heavily: Labour has sustained double-digit leads in national opinion polls for more than a year.

About one-third of England’s council seats are being contested on Thursday, and 10 mayoral seats in major English metro areas, home to about a third of Britain’s population, are also up for election.

What can the local elections tell us about a general election?

The big questions are how widely Labour can advance and how far the Conservatives may fall back.

British local elections have plenty of quirks — turnout is often relatively low, and smaller parties and independent candidates can do disproportionately well. But Thursday’s voting includes contests across England and Wales, and if the opposition’s apparent strength is less than opinion polling has suggested, the results should reveal that.

These elections are also a test of some new voting rules, under the Elections Act of 2022. It is the first time that all voters will need to show photo identification, which some rights groups say could disproportionately affect marginalized communities. The same law also changed the rules for electing mayors and police commissioners: Those races are now first past the post, meaning each voter has one vote, and the single candidate who gets the most votes in each constituency wins. That replaces a type of preferential voting in which voters could indicate a second choice.

Who is running?

Labour and the Conservatives are running candidates nationwide, as are the centrist Liberal Democrats. The Green Party is also increasingly competitive in some local elections. But a rising competitor on the right — Reform U.K., founded by the Brexit campaigner Nigel Farage — is running relatively few candidates, especially for a party that now places third in many opinion polls.

The highest-profile candidates are three incumbent mayors. For Labour, there’s Sadiq Khan, who is seeking to become London’s first three-term mayor since the citywide post was created in 2000. On the Conservative side, the big names are Ben Houchen in Tees Valley and Andy Street in the West Midlands. To win re-election, they will likely need to strongly outperform their party, which both have done in the past.

There is one parliamentary special election, or by-election, in Blackpool South, a deprived seaside district where the Conservative lawmaker Scott Benton has stepped down amid a lobbying scandal. Labour held the seat until 2019 and has strong expectations of winning it back.

Overall, voters will be electing more than 2,500 council members as 107 councils hold scheduled elections and 48 hold by-elections. With so many seats to fill, the list of candidates is long, and some contests will be watched more closely than others.

Prof. Tony Travers, director of the Institute of Public Affairs at the London School of Economics, said he would be closely watching the races in North East Lincolnshire, Hartlepool and Dudley to gauge changes in sentiment in what is known as the “Red Wall” — former Labour strongholds that the Conservatives won under Boris Johnson in 2019.

What are the main issues?

The economy, health and immigration have emerged as the three key issues for voters in Britain, according to polling from YouGov, which tracks public sentiment. Still, in these types of elections, national priorities can sometimes be overshadowed by local issues and the candidates’ personalities.

In May 2023, when the last local elections were held, the Conservatives held 33 percent of all council seats in England, and Labour held 35 percent, becoming the party with the largest share of council seats for the first time since 2002.

The Institute for Government, an independent British think tank, has noted that the Conservatives have been preparing for “a primarily defensive election,” hoping to hold on to the few councils they control and retain seats in places where they are the largest party but lack an absolute majority.

Who is expected to win?

Local elections in Britain are notoriously hard to predict, but most analysts agree that the Conservatives will face a real challenge, especially since most of these races were last run in 2021, a high point for the party after the early success of Britain’s Covid vaccination program.

Prof. Sara B. Hobolt, from the London School of Economics, suggested in a recent briefing that the Conservatives could lose as many as 500 council seats.

Labour’s five incumbent mayors have looked well placed to retain their seats — though Mr. Khan’s last race in London was significantly tighter than polling suggested.

For the Conservatives, Mr. Houchen has a strong following in Tees Valley — he won 72.8 percent of the vote in 2021 — but appears to be in a closer race this time, and polls suggest that Mr. Street is slightly trailing his Labour opponent in the West Midlands. If both of those mayors are unseated, it could be a major blow to Mr. Sunak’s leadership.

When will we learn the results?

Some votes will be counted overnight on Thursday, with results early Friday, while others will be tallied by Friday or Saturday afternoon. Although there will be a sense of how the Conservatives are performing by Friday afternoon, some critical results will be slower to emerge.

In the closely watched mayoral races, only the Tees Valley result is expected on Friday. The authorities in London and the West Midlands both plan to announce their results on Saturday afternoon.

Where can I find more information?

Britain’s Electoral Commission, an independent body that oversees elections in the country, has an in-depth guide to the local elections, how voters can register, and other specific guidance. The Institute for Government has laid out in granular detail the key things to look out for in the elections.

The New York Times will also cover the results.