Andy Street is Mayor of the West Midlands, and is a former Managing Director of John Lewis.

The phrase ‘levelling up’ has become one of the early political buzzwords of the new decade. Emboldened by its enlarged Commons majority, the Government has committed to invest in ways that ‘level up’ the economic fortunes of the regions and communities that feel they have been left behind.

This must be one of the central missions of the Government over the next four years. The election saw Labour’s ‘Red Wall’ crumble, returning Conservative MPs in Midland and Northern seats where Tory candidates have never expected to win in the past.

Voters who broke the habit of a lifetime to vote Tory expect to see us deliver on promises to ensure that real investment reaches beyond Watford. With two months to go until the Budget, it is time to put our money where our mouth is.

The key to realising this ambition to spread economic growth to the rest of the UK is the re-wiring of the Treasury that is said to be going on behind the scenes.

It has been reported that the Treasury is considering changing one of its formal objectives from ensuring strong economic growth ‘across all regions’ to ‘levelling up’ the rest of the UK with the south-east, partly through new national infrastructure strategy.

This would be achieved through infrastructure investment, a higher minimum wage and a greater focus on skills and vocational education.

I am hugely encouraged that we have a West Midlands man at the centre of this new financial direction in Sajid Javid, whose Bromsgrove constituency shares many of the economic challenges faced by communities across the UK.

Announcing the date of the budget in Manchester last week, he promised it would “set out ambitious plans to unleash Britain’s potential, level up across the UK and usher in a decade of renewal”. However, this can only happen if we get to grips with Treasury mandarins and their financial rules, which often seem to work against us.

The argument is that, by following rules that focus on the overall national impact of investment, and backing already successful regions, they risk just backing London and the South East.

Known as the ‘Green Book’, these Whitehall rules are said to impose a bias on infrastructure investment towards London, by directing public money to areas where productivity and prosperity are already higher. In simple parlance, they back a horse that is already winning.

While this approach may have ensured a relatively reliable return on investment in simple fiscal terms, it has also prevented regional investment for decades. Of course, when it comes to allocating public money, rules are important. It’s vital that investment drives tangible growth. Spending should never be purely for party advantage. But after years of talk about rebalancing the economy, the time has come for us to look again at the rule book.

It’s time to recognise the business case for investment in the Midlands which will allow us to power forward and deliver on our huge potential. My fellow Metro mayors and I have argued that further devolution of regional powers will inject new confidence into the industrial powerhouses of the Midlands and the North. Now it’s time to rip out the Treasury red tape that holds us back in terms of investment.

The West Midlands can provide proof that stepping outside those rigid rules can reap real dividends. When Phillip Hammond was Chancellor, I pitched an ambitious housing plan that required him to take a more nuanced view of those Whitehall rules than was usually reflected in his spreadsheets.

The result was a £350 million Housing Deal which is enabling us to deliver our ‘brownfield first’ approach to house building which is critical to providing homes, regenerating communities and easing the pressure on our green fields. While it may not have sat perfectly within the existing Green Book rules, that decision made absolute business sense.

But ‘levelling up’ isn’t just about crude fiscal investment – it’s about reaching out to those communities who feel that they have missed out on the economic success of other places. In the West Midlands, we are working hard to ensure that those areas in Coventry, Birmingham and the Black Country that have been ‘left behind’ receive the support they need.

A new era of national investment in infrastructure and skills, supported by rethought Whitehall rules, will help in this much-needed renewal. However, we must be realistic about what can be achieved and not expect immediate change. Investment in the regions would, without doubt, enhance productivity, but rewriting the rules means not only rethinking what qualifies an area or project for investment, but what results we should expect.

We in the regions must also accept that it will be up to us to identify the areas where public money will make the most difference and provide the detailed data to help monitor the success of investment made. We stand ready to do that and, if our calls for further devolution to the regions are heard, we can use the power of local decision making to grasp the opportunities offered by the Chancellor’s ‘decade of renewal’.

We don’t want a hand-out: we want to share in the prosperity experienced in the South. If ‘levelling up’ delivers one thing, it ought to be a level playing field for the UK’s regions.