With just hours before polls open for the local elections, senior Conservative and Labour figures have been thrashing out an age-old question: which party charges the most council tax?

Boris Johnson tweeted today: “Conservative councillors deliver better local services for lower council taxes”, echoed by cabinet colleague Oliver Dowden: “Conservative councils charge the lowest taxes in the country”.

Conservative minister Victoria Atkins said on last night’s Channel 4 News: “If you look across the board at the cheapest council tax councils in England, they are Conservative.”

To which Labour’s Wes Streeting replied: “On average, council tax in Labour councils is £329 lower than they are in Conservative authorities”. He suggested the FactCheck team look into it.

So here goes.

Conservatives charge lowest council tax in England?

How much council tax you pay depends partly on which of eight “bands” your home falls into. The categories are based on the value of the property in 1991. Right in the middle is Band D – which is what we often talk about when council tax is on the agenda.

But as the fact-checking charity FullFact has previously pointed out, the Band D rate only tells us part of the story. It is, after all, based on a 30-year-old system that can’t keep up with changes in property prices and local demographics. A more helpful metric is often the “average council tax per dwelling” (though as FullFact explains, it is not perfect).

By both the Band D and the average tax per dwelling measures, it’s true to say that the two local authorities with the lowest council tax bills in England are indeed led by Conservatives. (They’re Westminster and Wandsworth).

But it’s harder to sustain Ms Atkins’ claim that the same is true “across the board”.

FactCheck analysis of government data finds that Conservatives control five of the top ten cheapest areas by Band D rates, and ten of the top 20.

And when we rank councils by average tax per dwelling, Conservatives only control two of the cheapest 20 local authorities in England.

Labour charging hundreds less?

What about Mr Streeting’s claim that Labour councils charge £329 less on average than those led by Conservatives?

The figure comes from analysis by the Labour office of the Local Government Association, which used official data from the government. FactCheck was able to replicate this finding using the same dataset.

The same Labour LGA analysis found Liberal Democrat councils charged the most on average: £1,772 versus £1,642 from the Conservatives and £1,313 from Labour.

We understand that the Conservatives prefer to use the Band D measure as, according to the Department for Levelling Up, Housing and Communities, “this definition is widely regarded as a benchmark when comparing council tax levels in different areas or over time.”

The same publication points out that “Band D has historically been used as the standard for comparing council tax levels between and across local authorities, as this measure is not affected by the varying distribution of properties in bands that can be found across authorities.”

By this measure, the difference between the two largest parties is more modest – with Labour councils charging £40 less on average than the Conservatives, according to the LGA Labour analysis that FactCheck has reviewed.

FactCheck verdict

It’s true that the two local authorities in England with the lowest council tax bills are run by Conservatives.

On average, council tax “per dwelling” is £329 lower in Labour-run English councils compared to Conservative local authorities. Comparing Band D properties, the difference between the two parties is more modest (£40).

That’s according to Labour-led analysis that FactCheck was able to replicate using official government data. The same analysis found that, of the three parties, the Liberal Democrat councils charge the most on average per household.