Until very recently there was a prolonged period where the Government could borrow at 0% or even negative interest rates. It is absolute economic insanity for them to have not done so and implemented an enormous investment program, in a country that had zero productivity growth, skills gaps and failing infrastructure. Instead, they implemented an austerity program which made these problems worse.
Investments have a return. So yes they involve outlay, but well-planned investment with a proper industrial strategy leads to higher returns: increased growth and productivity, and more tax for the treasury. A proper industrial strategy of this nature then encourages business investment. And yes, there is significant business capital around the world that can be obtained, if you create an investable environment in this way. If, on the other hand, you let your infrastructure fall apart, create huge skills gaps, have no industrial policy to grow key sectors, and then erect huge and expensive barriers to trade, clearly you are not creating an investable proposition. This is why an increasing proportion of the UK economy consists of low skilled, low paid, low margin work.
It isn't rocket science. And it is the reason that other countries even despite interest rates now being higher and Government debts already high due to Covid, are creating large scale investment funds anyway. It is a necessity to remain competitive. Provided you have competent people who understand business and economics in charge of the program (i.e. none of our current MPs) it is still possible to implement such a program successfully - you simply have to ensure that there is a proper cohesive and integrated strategy, not the piecemeal throwing around of funds at random projects like with the "levelling up funds", to ensure that the ROIs exceed the interest rates, in real terms. This requires competent people making the decisions with a long-term view. And to rejoin the single market and customs union, of course.
If we do not raise business investment and productivity then not only will productivity (and therefore salaries and living standards) continue to fall, the value of GBP will also fall further which is very bad news for anybody struggling with living costs because that also makes imports more expensive and we import large proportions of essentails such as energy and food.
This is all basic economics.
To make this work as I said you also need people to have an incentive to work, therefore the bottlenecks caused by universal credit thresholds, CB thresholds, tax free childcare threshold, higher rate tax threshold, and the threshold for removal of the personal allowance all need addressing also because currently these are hugely impeding productivity and growth.
For a Government who apparently believe in market forces they appear to have an astonishingly low level of comprehension of how markets function.