Chris Mason: What this week's local elections mean for national politics

Wherever you live in England and Wales, you have a vote on Thursday.

Assuming, that is, you decide to use it and you are on the electoral roll.

There are elections for:

• 11 mayors in England

• 107 councils in England

• 37 Police and Crime Commissioners in England and Wales

Oh, and there is a Westminster by-election too, in Blackpool South.

More than 2,660 council seats are up for grabs, with the Conservatives and Labour each defending a similar number - just under 1,000 each.

The Liberal Democrats are defending just over 400, the Green Party just over 100.

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Will the Conservatives do badly?

The widespread expectation, among Conservatives and others is: Yes, they will.

Given that much is assumed, the big question is how badly - and how the outcome is perceived on their own side?

The seats being contested on Thursday were, in the most part, last fought in 2021.

At the time, the Conservatives under Boris Johnson were flying high, benefiting from a bounce in popularity courtesy of the Covid vaccination programme.

The elections coincided with a Westminster by-election in Hartlepool, which led to a Conservative gain over Labour, and Sir Keir Starmer's lowest moment as Labour leader.

It was so bad for him, he considered resigning.

How things have changed.

It means the Tories have a long way to fall this time, if that is the electorate's collective judgement.

What is a good or bad result for the Conservatives and Labour?

These results matter for their own sake.

They will decide the decision makers over all sorts of aspects of daily life in their areas for the next few years.

But they will also be used as a measure of the popularity or otherwise of the only two parties likely to lead a UK government - the Conservatives and Labour.

If the Conservatives:

• Lose 315 seats, that would be about the same proportion as last year

• Lose 480 that would be equivalent to their worst ever local elections performance, in 1995 - two years before they lost a general election by a landslide

• Lose 615 that would be a similar proportion to Labour's worst ever local elections performance, in 2009 - a year before they lost a general election.

Then there is what is called the Projected National Share.

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. Electoral experts Professor Sir John Curtice and Professor Stephen Fisher explain it in more detail here.

For context, last year Labour had a nine percentage point lead over the Conservatives. In 1995 their lead was 21 percentage points; in 1996 it was 16 percentage points.

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What about the races to be mayor?

Mayors are fashionable. They are often regional figures with a national profile.

And they are popping up in new places this time, such as the East Midlands and North Yorkshire.

Two contests stand out. They could prove to be the psychological see-saw upon which Conservative sentiment about all these races tilts.

The West Midlands and the Tees Valley.

Both are currently held by the Conservatives, but can they hang on?

Both the Tories and Labour are indulging in expectation management.

"Labour are throwing everything at it," says a senior Conservative about the Tees Valley contest.

"Remember they [the Conservatives] won with more than 70% of the vote last time," counters a Labour figure.

In the West Midlands, opinion polls have suggested it is mighty close.

And here is the psychology bit: losing Council X to "No Overall Control" might just be notable locally, but the outcome for a quasi-national figure like a metro mayor will grab more national headlines.

And the impact of these results on the mood of Conservative MPs in particular - who hold Prime Minister Rishi Sunak's short term fate in their hands - matters.

If the results are cataclysmic for them and they lose both these mayoral contests and a swathe of council seats too, do a critical mass of Tory MPs become willing to topple the prime minister?

If, on the other hand, the party chalks up a flagship victory here or there, does that stem the anger and the desire for action?

Where else should we watch out for?

There are contests for seats on 107 councils in England. This is a lot less than last year, when 230 local authorities had elections.

And, three quarters of those having elections this week are only electing a third of their councillors.

Here are a few places to keep an eye on, but this is not exhaustive.

How well do Labour do in Hartlepool, Redditch, Milton Keynes and Hyndburn?

Do the Conservatives lose in Dorset, Nuneaton and Gloucester?

Can the Liberal Democrats gain in Wokingham, Dorset and Tunbridge Wells?

And can the Greens make gains in Bristol, Solihull and Stroud?

For a far more comprehensive read on all this, take a look at this from the Local Government Information Unit.

Then there is Blackpool South. This is the one Westminster seat being contested this week, after the resignation of the former Conservative MP Scott Benton.

Senior Labour figures are confident of victory on the Lancashire coast.

They are armed with data, I am told, that points clearly in that direction.

It is the sort of place that is a must win for Labour leader Sir Keir Starmer.

Worth watching out too for Reform UK's performance in Blackpool.

Could they beat the Conservatives and take second place?

The result will be a big contributor to the moods of the parties on Friday morning, in what will be a long weekend of results trickling through from across England and Wales.