Sick of the slogan, Get Brexit Done? The new Conservative party mantra will almost certainly infuriate or seduce, depending on your view about the EU referendum. It may also be time-limited, depending of the outcome of the next few weeks.

The strapline, however, Invest in our hospitals, schools and police, is designed to live on into a fantasy post-Brexit world, where the Conservatives are reborn as the party of public spending and commitment to public services.

So, let’s get real. If you are a parent, teacher or governor in a school struggling with shrinking budgets and rising costs, do you break out the champagne now?

Much has been made of the £14bn “boost” to school budgets over the next four years. According to the Institute for Fiscal Studies, that £14bn becomes £4.3bn in today’s money by 2023 once you strip out inflation and triple-counting of each year’s increase.

That is not an insubstantial sum – a 7.4% increase on today’s spend. However, school funding has dropped 8% overall since the coalition government came to power in 2010, so in four years’ time we will be back where we were 13 years before.

Rather like the much-vaunted parallel promise to provide 20,000 new police officers to replace 20,000 old police officers cut during the austerity years, this is not investment. Investment is putting money in to get a return of some sort. This is plugging a painful gap.

Much has happened since 2010. Cuts have been made and consequences felt. There are 700,000 more pupils in the system and teacher applications are slowing down. For many schools, making efficiencies and staying solvent has meant cutting subjects, enrichment activities and teachers while increasing class sizes at a time of radical change to the curriculum and exams.

They also feel the 40% cut in capital funding, shrinking sixth form budgets, the increase in poverty and the decimation of essential local authority services needed to help the most vulnerable students flourish and stay safe. None of this can be wished away.

And schools need money now, not in four years’ time. Five of the unions living and working closer to the real world than the prime minister will ever be have stated that, in spite of the extra funding promised, more than 80% of schools will have less money per pupil in real terms in 2020 than in 2015. The most deprived pupils will be the hardest hit at a time when progress in narrowing gaps is slowing.

Boris Johnson, whom I suspect has very little real understanding of state schools, likes to colour his government’s funding pledge with the vacuous promise that the money will be used to “level up”. But what does that mean? Levelling up to 2010? Levelling up to the gold-plated Eton education he experienced, or to the comfortable standard his own children enjoyed in private London day schools? This would cost at least an extra £15,000 per pupil per year, so unlikely.

Even the promise of closing the gap between the best and worst-funded local authorities seems unattainable. The new minimum funding guarantee of £5,000 for each secondary pupil, and £4,000 for each primary pupil, will leave glaring differences between different parts of the country and even between pupils with similar needs in the same area. And all this without knowing the consequences of Brexit on the economy and public expenditure.

It is an interesting thought experiment to speculate on where we might be now if school budgets had continued to rise at the 5% a year that typified the genuine investment of the last Labour government. Then compare that with the next few years. The truth is that this Tory promise isn’t investment and it won’t “level up” in any meaningful way. The champagne will stay on ice.