Boris Johnson likes to insist that his commitment to levelling up is “absolutely rock solid throughout this country”.

Yet in many parts of the country, including throughout much of Yorkshire, our property taxes tell an entirely different story – council taxes that are both rising up and levelling down.

Batley and Spen, where Labour and the Conservatives will go head-to-head in a by-election battle on July 1, is one constituency that clearly gets a rotten deal under the current system.

That’s because council tax works for the millionaires rather than the millions. It ensures that people who live in modest houses are paying a higher tax rate than those living in the wealthiest areas.

It is also hitting renters saving up for a deposit just as hard as those who have already made it onto the property ladder.

The unfairness of the current system is underlined by the fact that residents of Westminster presently pay out just 0.06 per cent of their home’s value in council tax every year.

Yet across Yorkshire and Humber this “council tax burden” leaps up to 0.76 per cent. In Batley and Spen it climbs further to 0.87 per cent.

That means we currently have the absurd situation in which residents of Batley and Spen face a council tax burden 15 times higher than people living in Westminster.

The vast majority of residents in Batley and Spen and nearby would be far better served if the Government was to scrap council tax and stamp duty and bring in a simple proportional property tax, as proposed by the Fairer Share campaign.

Set at a flat rate of 0.48 per cent of a property’s value, this tax would bring in exactly the same amount of revenue as stamp duty and council tax and would mean lower bills for 19 million households across England.

There would also be safeguards in place to ensure that only those who can afford to pay more do so.

Under proportional property tax, any increase in property tax is capped at £1,200 and those who cannot afford to pay the tax have the option to defer payments and pay a modest interest rate.

Across the UK, more than 120,000 households have signed the Fairer Share petition calling for a proportional property tax.

In constituencies near Batley and Spen, MPs have also made it clear that they believe in a fairer system of property tax, with the policy cutting across party lines.

One key supporter of proportional property tax is Kevin Hollinrake, the Conservative Party MP for Thirsk and Malton who set up the Property Research Group of MPs to fight for reform of outdated property taxes.

Earlier this year Boris Johnson was asked about the policy at Prime Minister’s Questions when it was noted that a proportional property tax “would create a transparent property taxation system, generate revenues that local government needs and ease the tax burden on hard-pressed families across the country”.

As Batley and Spen gears up for the by-election, both the Labour and Tory leaderships should take note.

If the Conservative Government is really committed to making the country fairer then support for a proportional property tax should be a no-brainer, showing voters that there is more to levelling up than mere rhetoric.

And if the Labour Party is serious about reconnecting with lost voters on July 1, how better to prove the point than getting behind a policy that would mean big savings every year for the households throughout the constituency?

With council taxes skyrocketing, what Batley and Spen does not need is an MP who toes the party line if it fails to deliver for local people.

Unfortunately, our current property tax system does exactly that and we urgently need to open the door to a fairer alternative.

Bringing in a proportional property tax would result in lower bills for 76 per cent of households across England.

In Batley and Spen it would mean lower bills for 99 per cent of households, with average savings of £650. That’s something that voters could see as a rock solid commitment to levelling up.

Andrew Dixon is the founder of Fairer Share