The received Westminster wisdom is that the local elections are do-or-die for Boris Johnson.

After months of awful headlines about partygate, and with the mood among Tory MPs once again turning fractious, a bad night for the Conservatives next Thursday may well be the trigger for a move to unseat the prime minister.

What is less discussed, however, is how the elections are also a key test for Keir Starmer and whether he has what it takes to lead Labour to victory at the general election in two years’ time.

With a new poll yesterday giving Labour a nine-point lead over the Conservatives, expectations are high that the party is set to make sweeping gains on Thursday.

But Starmer’s internal detractors are looking for any signs that the party is stalling to confirm their suspicions that he is failing to seal the deal with voters.

Here, HuffPost UK assesses where the main parties are ahead of a crucial night on May 5.

A total of 6,812 council seats in England, Wales and Scotland are up for grabs on Thursday.

In addition, there are also mayoral elections in South Yorkshire, Hackney, Lewisham, Newham, Tower Hamlets, Watford and Croydon, as well as the Northern Ireland Assembly election.

In England, the Tories are defending 1,404 seats, Labour 2,222 and the Lib Dems 517. The rest are held by independents.

In Wales, Labour hold 462 council seats, with Plaid Cymru on 208, the Conservatives on 197 and the Lib Dems on 59. More than 300 seats are held by independents.

And in Scotland, the SNP have 432 seats, with the Tories second on 277, Labour on 262 and the Lib Dems on 67. Nearly 200 of Scottish councillors are independents.

An awful lot more than which parties will be responsible for your bin collections for the next four years.

With a general election expected in 2024, this is likely to be the last big electoral test that Labour and the Tories will face before then.

As such, it will act as an important barometer of the national mood and indicate which parties, if any, are starting to build up momentum as the general election draws nearer.

Johnson needs to prove to his restive MPs that he is still the election winning-machine who delivered an 80-seat majority in 2019, and that the damage done to his reputation by partygate is not terminal.

The stakes are arguably even higher for Starmer who, two years after becoming Labour leader, has still to convince the public that he has what it takes to lead the country.

While Labour has established a consistent poll lead in recent months, there remains a strong suspicion that it owes more to the public’s dissatisfaction with the Conservatives than any great enthusiasm for the Starmer project.

HuffPost UK revealed this week that the Labour leader is facing internal pressure to show voters how the party would tackle the cost of living crisis rather than focusing on the partygate scandal.

At a shadow cabinet meeting, communities spokesperson Lisa Nandy said Labour risked looking “out of touch” at a time when families across the country are struggling to make ends meet.

One senior frontbencher said: “Lisa’s not alone on this. There was strong agreement in the room to focus on the cost of living.”

It’s clear, therefore, that Starmer’s critics will be scrutinising Thursday’s results to try and assess whether the public support the leader’s strategy or are yet to be convinced.

The main problem facing Labour is that the last time these council seats were up for grabs four years ago, the party did very well, making it harder for them to make sweeping gains this time around.

That said, a failure to pick up a significant number of council seats, and at least show progress in the Red Wall areas the party needs to win back if it’s to stand any chance of winning in 2024, will constitute a disappointing evening for Starmer.

“It’s a strange set of elections,” said one Starmer ally. “2018 was a bad night for the Tories and a very, very good one for Labour.

“So another bad night for the Tories and a good night for us isn’t going to result in a lot of exciting change.”

As polling gurus Colin Rallings and Michael Thrasher summed up the situation in a recent article: ”[Labour] will do well to avoid making standing still rather than picking up gains seem rather underwhelming when the post-mortem takes place.

“For the Conservatives, by contrast, the less dramatic the results, the more they can claim not to be suffering traditional ‘mid-term blues’.”

Labour sources are attempting to play down the prospect of the party seizing totemic Tory councils like Westminster and Wandsworth, but they admit that winning back Barnet is a distinct possibility.

Beating the Tories into second place behind the SNP is also essential if the party is to have any hope of re-establishing an electoral foothold in its former Scottish heartland.

Just as important as winning more council seats, insiders say, are signs of progress in seats currently held by the Tories in England and the SNP north of the border.

“We are also tracking where we are in about about 50-70 constituencies that would put us in government at a general election, so we will be keeping an eye on them on Thursday,” said a Labour source. “Places like Stevenage, Wakefield, Bury and Glasgow.

“We need to beat the Tories and SNP in them.”

Unsurprisingly, the Conservatives are keen to raise the bar as high as possible for what would constitute a good night for Labour in the hope they will come nowhere near clearing it.

One Tory source told HuffPost UK: “Labour are obviously saying how difficult it’s going to be to improve on 2018, but the reality is they are ahead in the polls and so should be doing well.

“It’s going to be very difficult for us in certain places, especially central London and in places like Wandsworth, Westminster and Kensington and Chelsea, where the demographics are turning against us.

“Outer London is a bit better, but things are also going to be difficult in the affluent south – places like Surrey and West Oxfordshire, where Labour are doing well.”

Significantly, however, the Tories are more confident of holding off Labour in the Red Wall, where partygate is not the major political issue many at Westminster believe it is.

“The question for Labour is whether they can make adequate progress in the places they lost in 2019 and need to win back next time,” the source said.

“While those voters are bothered about partygate, they’re more concerned with bread and butter issues such as the cost of living. They’re pissed off with the PM about partygate, but they also like what we did on vaccines and furlough.”

Like Labour, the Lib Dems performed well in 2018, making further progress more difficult this time around.

“What we’re really looking to is consolidate the gains we made in places like South Cambridgeshire, Richmond and Kingston,” a source told HuffPost UK. “If we hold our ground and edge forward a little in other areas, it should spook a few Tory MPs.”

These include Stephen Hammond in Wimbledon, where the Lib Dems launched their local election campaign. The party also wants to make progress in Wokingham, where the local MP is one Dominic Raab.

The source added: “The big picture is we’re going after the Conservatives and laying the groundwork for the next election.”

In the past week alone, unnamed Tory MPs have smeared Angela Rayner by accusing her of using her legs to distract Boris Johnson, while another has been suspended by the party for allegedly watching porn in the Commons.

The timing could hardly have been worse for the Conservatives. Will voters use their ballots to register their disgust at the latest examples of Tory sleaze? Keir Starmer and Labour certainly hope so.