If, as some are predicting, Labour does well at the local elections next week, will it mean Jeremy Corbyn is on the way to Number 10? If there is any sign of a Lib Dem recovery in London, will it mark a return to pre-2010 politics? And if the Conservatives hold on to key councils across England, will it be proof that the country agrees with Theresa May on the direction of Brexit?

Well, yes, and no. Local elections are sometimes seen as a signifier for national ones; conventional wisdom suggests parties that do well in them will see this replicated in the future. While councillors and hopefuls fight on local issues – potholes, library closures, bin collections – few voters make their decisions purely on that basis; for many of them it is a chance to give the national party a kicking or register their dissatisfaction about the direction of current politics. It’s logical, then, that local elections are seen to be a weathervane; a taking of the country’s temperature.

In reality, however, that’s not always the case. On May 3rd many of us will go to the polls, including every London borough, 34 Metropolitan boroughs, 68 district and borough councils, and 17 unitary authorities (along with the mayoral election for the Sheffield City Region). These elections largely last took place in 2014, at which Labour won 2,121 seats and held or won a total of 82 councils, surpassing the 1,364 seats and 41 councils taken by the Conservatives (representing a significant decline). Perhaps that – along with the pollsters getting it wrong – explains why so many expected Ed Miliband to lead his party to victory in 2015, or at the very least secure a hung Parliament. In the event, as we all know, he barely came close.

And perhaps more pertinently, the beating suffered by Labour at the local elections held in May 2017 – in which Labour lost 320 council seats and the Conservatives emerged victorious in a series of mayoral races – reinforced expectations of a blue landslide at the surprise general election a month later. Again, that did not quite come to fruition.

At the same time, however, the 2014 results did point to future events, with the Lib Dems experiencing yet more losses, and a then potent UKIP seizing 163 seats in Nigel Farage’s so-called ‘political earthquake’. UKIP might not have replicated this a year later when the entire country went to the polls, but this (along with the swing to UKIP in the 2014 European elections) can certainly be seen as a forerunner for the Brexit vote the following year.

What’s clear is it’s complicated. In 1995, in the dying days of the Major Government, his party saw wounding losses of some 2,000 seats, and the picture was the same a year later. The 1997 New Labour landslide was clearly on the cards, and voters were making known their discontent with the Tories at the local level because they weren’t yet able to nationally. Likewise, the 1990 local elections came as the poll tax controversy hit the headlines, and saw the Conservatives lose 163 seats; a precursor to the rockier period ahead in which Margaret Thatcher was pushed out of office?

Yet by the same token, in 1991, amidst Thatcher’s downfall, the Conservatives experienced severe net losses and Labour received its best result in almost two decades. Despite this, the lights were not turned out in Britain as Neil Kinnock failed to translate this into national success. Similarly, in 2003, in the wake of the Iraq War decision and plummeting popularity for Tony Blair’s leadership, Iain Duncan Smith’s Conservatives gained more than 560 seats while Labour lost control of previously solid councils. Yet two years later, IDS was history and Blair was celebrating a historic third term.

On their own, local election results may not tell the whole story, but that’s not to say that any wider trends and patterns should not be noted by political parties. Clearly, the results reflect voter sentiment; in the case of next week’s ballot, if the Conservatives see their support plummet, Theresa May will be wise to examine why. After all, successful leaders are those that read the runes and respond accordingly. With up to four years before the next general election, there’s time to do so.

So will the upcoming local elections tell us anything about what the future of British politics holds? It’s uncertain – but beware of pundits and commentators making great extrapolations from the results. What is certain, perhaps, is that whichever party does better on Thursday will treat the outcome as a seal of approval. Whether they will be right to do so is another question.